Anal. Chem. 1988. 60,181 R-200R (293) Kramer, 0. H. Health Phys. 1084, 47, 623. (294) UtO, M.; Itoh. Y.f Sugawara, M. Fresenlus' Z. Anal. Chem. 1985, 327, 68. (295) k h h a n , M. C.; Tyczkowska, K. Spectrochm. Acta 1987, 428, 665. (298) SchmM, G. M.; Atherton, D. R. Anal. Chem. 1988, 58, 1956. (297) Guiimette, R. A. Health Phys. 1088, 57, 797. (298) Wong, S. T.; Spoo, J.; Kerst, K. C.; Spring, T. G. Clln. Chem. 1985, 37, 1462. (299) Andersen, I. Clin. Chem. 1988, 32, 321. (300) Parkinson, J. A.; Grimshaw, H. M. Commun. Sol/ Sci. Plant Anal. 1988, 77, 735. (301) Jeffrey, A. J.; Lyons, D. 4. Analyst (London) 1985, 170, 951. (302) Andsrsen, K. J.; Wkshaland, A.; Utheim. A.; Jukhamn, K.; Vik, H. Clln. Sbchem. 1988, 79, 166. (303) Bowen, H.J. M.; Sujari, A. N. J. Radioanal. Nucl. Chem. 1988, 106, 193. (304) Sujari, A. N.; Bowen. H. J. M. J. Sci. Food Agric. 1987, 3 8 , 367. (305) Jones, K. C.; Peterson, P. J.; Davies. B. E.; Minski. M. J. Int. J. Environ. Anal. Chem. 1085, 2 7 , 23. (306) &la. P. G.; Cruclatti, A.; Mazzoiini, S.; Tonutti, E.;Nador, G.; Bramez28, M. G. Ital. Chim. Clin. 1985, 10, 131. (307) Mann, S. W.; Green, A. Ann. Clin. Slochem. 1987, 2 4 , 117. (308) Bolnk, F. B. T. J.; Bljster, P.; Yink, K. L. J.; Maas, A. H. J. Clln. Chem. 1985, 37,523. (30s) Florence, E. Analyst (London) 1086, 7 7 7 , 571. (310) Razmilic, B. B. At. Spectrosc. 1988, 78 43. (311) Yagi, M.; Masumoto. K. J. Radbanal. Nucl. Chem. 1985, 9 0 , 91. (312) Masumoto, K.; Yagl, M. J. Radbanal. Nucl. Chem. 1985, 9 1 , 369. (313) Catatin, S.; Doretti, L.; Mazzl, U. Health Phys. 1985, 49, 795. (314) Grases, F.; Far, G. Radiochlm. Acta 1988. 3 9 , 61. (315) Martinez-L., A.; Garcia-L., M.; Madurga, 0. Appl. Radiat. Isot. 1988, 3 7 , 438. (316) Leloux, M. S.; Nguyen, P. L.; Claude, J. R. At. Spectrosc. 1987, 8 , 75. (317) Ponikarova, T. M.; Popov, D. K.; Bekyasheva, T. A. Gig. Sanit. 1985, (g), 67. (318) Ahrarez, G. H.; Caper, S. G. Anal. Chem. 1987, 5 9 , 530. (319) Outierrez, A. M.; PerezC., C.; Rebollar, M. P.; Polo-D., L. M. Talanta 1985, 32, 927. (320) Krull, I. S.; Panaro, K. W. Appl. Spectrosc. 1985, 3 9 , 960. (321) Cary, E. E.; Grunes, D. L.; Bohman, V. R.; Sanchirico, C. A. Agron J. W88, 78, 933. (322) Capitan*., F.; Salinas, F.; Martinez-V., J. L.; Pino, J. L. Mlcrochem. J. 1985, 3 2 , 313. (323) Kelly, W. R.; Fassett, J. D.; Hotes, S. A. Health Phys. 1087, 52, 331. (324) Vartanlan, R. J. Radloanal. Nucl. Chem. 1988, 704. 285. (325) Wang, M.; Duan, Y.; Zhang, L. Fenxi Huaxue 1985, 13, 400. (326) Sharma, P. K.; Lai, N.; Nagpaul, K. K. Health Phys. 1985, 48, 609. (327) Hattenhorst, A.; RethfeM, H. Fresenius' Z.Anal. Chem. 1985, 327, 596. (326) Bermejo-B., P.; Bermejo-M., F.; Cocho de Juan, J. A. J. Anal. At. Spectrom. 1987, 2 , 163. (329) Matsubara, I. Bunseki Kagaku 1988, 3 5 , 38. (330) Fassett, J. D.; Kingston, H. M. Anal. Chem. 1985, 5 7 , 2474. (331) Hernandez-C., M.; Vinas, P.; Sanchez-P., C. Analyst (London) 1985, 110, 1343.
(332) Chwastowski, J.; Koslaraska, E. Chem. Anal. (Warsaw) 1985. 3 0 , 395. (333) Yamada, H.; Hattori, T. J. Chromatop. 1988, 361, 331. (334) SimOnSen, K. W.f NUsen, 6.;Jensen, A.; Andersen, J. R. J. Anal. At, Spectrom. 1986, 1, 453. (335) Homsher, R.; Zak, 8. Clln. Chem. 1985, 3 7 , 1310. (336) Serfass, R. E.; Thompson, J. J.; Houk, R . S. Anal. Chim. Acta 1988, 788, 73. (337) Kashlwabara, K.; Hobo, T.; Kobayashi, E.;Suzuki, S. Anal. Chlm. Acta 1985, 778. 209. (338) Cano-P., J. M.; Urena-P., M. E.;Garcia de Torres, A. Anal. Chem. 1988, 58, 1449. (339) Jln, W.; Xu, H. Fenxl Huaxue 1988, 1 4 , 541. (340) Ostapczuk, P.; Valenta, P.; Nuernberg, H. W. J. Electroanal. Chem. Intetfaclal Electrochem. 1988, 214, 51. (341) Burguera, J. L.; Burguera, M.; Alarcon, 0. M. J. Anal. At. Spectrom. 1988, 1, 79. (342) De Ruig, W. G. J. Assoc. Off. Anal. Chem. 1986, 6 9 , 1009. (343) Puchyr, R. F.; Shapiro, R. J. Assoc. Off. Anal. Chem. 1988, 6 9 , 666. (344) Nyarku, S. K.; Deimage. M.; Szturm, K. Anal. Chim. Acta 1988, 786, 307. (345) Bo, S.; Lan, X. Yaoxue Tongbao 1987, 22(1), 10. (346) Ottaviane, M.; Magnattl, P. J. Anal. At. Spectrom. 1986, 7 , 243. (347) Donhauser, S.; Wagner, D.; Jacob, F. Monatsschr. Srauwlss, 1987, 40, 247. (348) Shiralshi, K.; Tanaka, G.;Kawamura, H. Talanta 1988, 3 3 , 861. (349) Zeng, L.; ai, H.; Tian, S.; Bai, L. Fenxi Huaxue 1988, 14, 532. (350) Zeng, L.; Bai, L.; Xia, L.; Tlan, S . Fenxi Huaxue 1985, 13, 92. (351) Boorn, A.; Fuiford, J. E.; Wegschelder, W. Mlkrochim. Acta l98k, I I , 171. (352) Interesse, F. S.; D'Avella, G.; Alloggio, V.; Lampareiii, F. 2. Lebensm .-Unters. Forsch, 1985, 187, 470. (353) Klriyama, T.; Kuroda, R. Chromtographis 1988, 27, 12. (354) Oesch, U.; Ammann. D.; Simon, W. Clin. Chem. 1988, 3 2 , 1448. (355) Aref'ev, I. M.; Benyaev, N. E.; Komieva, A. A,; Ramendik, G. I.; Tyurin, D. A. Zh. Anal. Khim. 1988, 4 7 , 5 0 . (356) Goetz, A.; Heumann, K. G. Fresenlus' 2.Anal. Chem. 1987, 326, 118. (357) Hiipert, K.; WaMmann, E. Fresenlus' 2.Anal. Chem 1986%325, 141. (358) Ward. N. I. J. Micronutr. Anal. 1988, 2 , 211. (359) Awadallah, R. M.; Mohamed. A. E.; Gabr, S. A. J. Radioanal. Nucl. Chem. 1985. 9 5 , 145. (360) Iskander, F. Y.; Morad, M. M. J. Radloanal. Nucl. Chem. 1988, 705, 151. (361) Iskander. F. Y.; Klein, D. E.;Bauer, T. L. J. Radioanal. Nucl. Chem. 1988, 9 7 , 353. (362) Hall, G . S.; Navon, E. Nucl. Instrum. Methods Phys. Res. 1986, 815, 629. (363) Liu, Y. W.; Harding, A. R.; Leyden, D. E. Adv. X-Ray Anal. 1988, 2 9 , 503. (364) Wang, N.; Chen, S.; Chen, J.; Zhang, D.; Feng, W. Nucl. Instrum. Methods Phys. Res. 1987, 822, 560. (365) Havranek, E.; Harangozo, M.; Bumbalova, A. J. Radioanal. Nucl. Chem. 1988, 107, 175. (366) Mishra, U. C.; Shaikh, G. N.; Sadaskan, S. J. Radloanal. Nucl. Chem. 1988, 702, 27.
Kinetic Determinations and Some Kinetic Aspects of Analytical Chemistry Horacio A. Mottola Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078-0447
Dolores P6rez-Bendito Department of Analytical Chemistry, University of CBrdoba, 14071 CGrdoba, Spain
Harry B. Mark, Jr.* Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221
This review retains, basicall ,the organizational structure The papers reviewed have of previous ones in this series been selected from thme that appeared since November 1985 and were available for the authors' consideration through approximately November 1987.
6).
'
0003-2700/88/O380-l8 1R.$O6.50/0
The general theme of this review is receivin considerable attention in professional meetings. The Seconf International Symposium on Kinetics in Analytical Chemistry met in Preveza, Greece, from September 9 to September 12, 1986. Highlights of ita sessions have been chronicled (2). The success 0 1988 American
Chemical
Soclety
181R
KINETIC ASPECTS OF ANALYTICAL CHEMISTRY
of this series is attested by the fact that the Third International Symposium is scheduled to take place in Cavtat, a small town looking at the beautiful Adriatic Sea, very near Dubrovnik, Yugoslavia, from September 25 through September 28,1989.Several meetings in the People's Republic of China (3) testify of the interest in that country. The first national conference on kinetic methods of determination organized by the Chinese Chemical Society took place from June 28 to July 4,1985,in Lushan (Jiangxi province). A total of 130 participants attended 60 presentations on the topic. The second conference of this type took place in Hefei (Anhwei province) from October 15 through October 22,1987. Reports of this meeting were not available to the authors at the time this review was prepared. Besides the Third International Symposium mentioned above, other get-togethers of scientists interested in the general topic of kinetics and analytical chemistry are being planned. A symposium on "Recent Advances in Kinetic Methods" is being arranged by Gary D. Christian (University of Washington) for the ACS National Meeting in Los Angeles (Sept 2530,1988).A symposium on "Kinetic Aspects in Analytical Chemistry" for the 1989 International Chemical Congress of Pacific Basin Societies (Honolulu, HI, Dec 17-22, 1989) is being organized by Takuji Kawashima (University of Tsukuba, Japan), Karl G. Blass (University of Regina, Canada), and Horacio A. Mottola (Oklahoma State University, Stillwater, OK). This international congress is sponsored by the Chemical Society of Japan, the Canadian Society for Chemistry, and the American Chemical Society.
BOOKS AND REVIEWS Textbooks aimed at analytical undergraduate training continue the trend, initiated some years ago, of making room for reaction rate considerations with focus on their analytical applications. The range of contributions in the past two years goes from a chapter dedicated to the topic in a new textbook ( 4 ) ,extensive updating and revision of material presented in a book on instrumental analysis (5),and unchanged reprinting of material presented in previous editions (6). A new monograph by one of the authors of this review has also been published recently (7). Several reviews have appeared covering catalytic determinations. Kamentseva et al. (8) have reviewed catalytic methods for the determination of organic species. The review includes methods based on primary catalytic effects as well as on inhibiting and activating effects of organic compounds on metal-catalyzed reactions. Catalytic determinations of platinum metals have been reviewed by Yatsimirskii and Tikhonova in a special issue of Talanta devoted to work in the Soviet Union (9). The analytical applications of the catalyzed iodine-azide reaction have been reviewed by Ramis Ramos et al. (10). Catalytic determinations adapt themselves, in the fixed-time mode, very well to unsegmented-continuous-flow systems and a review (in Japanese) of catalytic methods performed using such a form of sample/reagent(s) processing has been presented by Yamane (11). The impact of physical, chemical, and physiochemical kinetics on analytical selectivity has been surveyed by Valc6rcel (12). Mottola (13)reviewed the use of enzymes as analytical reagents for substrate determination. The review included the use of soluble as well as immobilized enzyme preparations. A very comprehensive review on catalytic end-point indication and catalytic titrants by Gag1 (14) covers the origins of the approach and its evolution up to the present stage of development. The development of gas chromatographic detectors based on chemiluminescence has been reviewed by Hutte et al. (15) and Gaget and Serpinet (16) reviewed the main kinetic equations involved in gas chromatography and the methods for the determination of the corresponding rate coefficients.
KINETIC METHODS FOR DETERMINATION OF CATALYSTS The number of catalytic determinations reported in the literature in the last two years is similar to that of the previous period review (1). However, the number of applications to real or synthetic samples increased by about 25%. Again, redox reactions were the indicator reactions most frequently used and transition metals-particularly manganese, copper, 182R
ANALYTICAL CHEMISTRY, VOL. 60, NO. 12, JUNE 15, 1988
vanadium, and iron-the species most commonly determined. As a rule, the mechanisms of the catalytic reactions on which such methods were based involve a transient metal-substrate complex in which the metal ion had an oxidation state different from that of the metal-catalyst ion. On the other hand, various catalytic reactions formerly used in a conventional manner and other navel systems have been used with the continuous-unsegmented-flowtechnique (FIA) and the trend to the application of the approach in kinetic methods seems to continue. Table I lists the methods proposed for the direct determination of catalysts reported over the last two years. A self-consistent method for the numerical determination of the rate coefficients of the catalyzed and uncatalyzed pathways in autocatalytic reactions was proposed by AndrBs-Ordax and Arrizabalaga (91). The experimental data obtained from kinetic runs, initially carried out without catalysts, were used for a leabt-squares treatment of the rate equation and both rate coefficients were optimized by an iterative procedure. The method was tested on the permanganatefthreonine system. A catalytic determination by continuous addition of catalyst formerly reported by Lbpez-Cueto and Cueto-Rejbn (92) received a more detailed description and its scope was broadened (93). The approach involves comparing the curve obtained for the sample solution with that of a reference solution to which a catalyst standard is added at a constant rate in order to find an "intersection time" from which the catalyst concentration can be obtained, either by direct means or by the use of calibration plots. Few kinetic methods using catalyzed reactions are for the determination of one of the components of the indicator reaction rather than the catalyst itself, probably because of a low sensitivity. Yet, Labuda et al. (94) recently reported the determination of dissolved oxygen based on its oxidizing action on ascorbic acid in a reaction catalyzed by the Cu(I1) complex with tetrabenzo[ b,fj,n]-1,5,9,13-tetraazacyclohexadecin. The duration of the induction period is proportional to the logarithm of the initial concentration of dissolved oxygen in the sample over the range 0.5-32 pg mL. The method can be applied to the determination of issolved oxygen in natural waters. Interfering Cu(I1) and Fe(I1) can be removed by precipitation with 8-quinolinol. Although hydrogen peroxide is one of the oxidants most frequently used in indicator reactions in nonenzymatic catalytic methods, it had not been determined by a conventional kinetic method until recently. The method in question is based on the Mn(I1)-catalyzed oxidation of 2-hydroxy-lnaphthaldehyde thiosemicarbazone by this oxidant (95). The reaction rate is monitored spectrofluorometrically. The method is one of the most sensitive described so far-the calibration curve is linear from 50 to 2000 nM-and was applied to the determination of HzOz in coffee (where it may be involved in mutagenesis), tea, and milk with good results. The same reaction system was used to develop a determination of organic hydroperoxides and lipohydroperoxides a t the nanomole level (96). The method allows the determination of tert-butyl and cumene hydroperoxides in 0.08-1.56and 0.12-3.3pM, respectively, and also permits one to establish the differences in reactivity between the hydroperoxides determined. When applied to the determination of hydroperoxides in commercial oil samples (grape seed, corn, sunflower seed, cod liver, and linseed), it provided results consistent with those found by iodimetry. The high sensitivity of all these methods can be attributed to the activating effect exerted by these peroxides on the manganese-catalyzed oxidation of the reagent by atmospheric oxygen. On the basis of the oxidizin action of technetium(VI1) on organic compounds such as o-fianisidine and diphenylamine, catalyzed by copper(II), a spectrophotometric method was developed for determination of Cu(I1) ion at concentrations between 0.2and 4 pg/mL (97) and applied to its determination in synthetic mixtures similar to nuclear fuel and seawater. Sensitive and selective Catalyzed reactions allow the indirect determination of species involved not in them but in other reactions resulting in the generation of the catalyst or one of the components of the indicator reaction. In this manner, cholesterol, amino acids (e.g. L-leucine, L-phenylalanine, and L-serine),and linoleic acid can de determined indirectly at the micromolar level with the aid of a very sensitive catalytic system for the determination of the HzOzgenerated by en-
d.
KINETIC ASPECTS OF ANALYTICAL CHEMISTRY HwacIO A. Monola. Rofesaor of Chemiaby. Oklahoma State University. wall born in Bwnm Aims. Argemina. and received his undergraduate and graduate education at Me University Of Bwnos Alro. He earned Licentiate and Doctoral degrees from me University of Buenos Alres and dld predoctorai w c h with PIofessor Ernest B. Sandell at Me University of Minnesota (Minnespalb). HB spem 2 years at the university 01 A ~ X ma (rucsan) as a postdocotral research associate in Professor Henry Freiser's reSearch group. Alter teachlib lw 2 years at ,' University of the Paclflc (Stackton. CA). he pined OSU in the fall of 1967. HIS research interests include studies m the role of kinetlcs in analytical chemistry (including reaction rate methods). chemical immbiiiratbn Of enzymes and chelating agents lor use in reaCtm in COminuOuS-fiOw systems, chemically modified electrDdes for sensing in now systems. analytical separation~.and photochromism of metal chelates. He 16 the s h o r of a recent monograph on "Kinetic Aspects of Analytical Chemisw.
Dolores P6rez-BBmdHo is cunentk Fmfessor Of Analytical Chemistry at the University 01 C6rdoba. Spain. She earned me Ph.D. degree In 1968 hom me University 01 Seviiie. Spaln. After 7 yean as Assistant PTofeuor at the universny Of Seviiie. she pined the Facuity of Sciences at the University 01 Cbdoba and since 1980 she has been B professor in the Department 01 Analytical Chemistry of this Institution. Pmfessor P&ez-Bendito'. research interests include *ace analysis. molecular opectrosmpy, and kinetic memods of determination with emphasls on diflerentiai rate methods and I catalytic determlnatlons wim photometric ., ' and nuwometric monnwing. She hes published extensively in mese topics and is me coaymo( of several textbcde and a monograph on "Kinetic Met+ ods in Analytical Chemistry".
7
Harry B. Mark, Jr.. PToIe~sorof Chemistry. University of Clnclnnati. rec~lvedhis B.A. degree from me University of Virginla in 1958 and his W.D. degree hom Duke Unkersw in 1960. He was a postdoctoral research associate at the University of N h Carolina (with C. N. Rellley) from 1960 to 1962 and at me caiifornia institute of ~ e d ~ nolog, (wim F. C. Anson) ham 1962 to 1963. ne was a member 01 me staff 01 me Department of Chsmisq at the University Of Michigan from 1983 to 1970. Visiting Pro. lessor of Chemism at me Universit6 Libre de Bruxellaes. 1970, and joined the staff at me univer~ny01 cincinnati in 1970. HB WBO , me Department Head from 1976 to 1981. His research ihterests are in elechochemlstry, surtace chemism. kinetic methods of analysis, environmental anaifllcal problems. and inshumentation. In addition to research papers. he Is the Coauthor 01 the books '"Klnetlcs in Analytical Chemistry", "Activated Carbon: Surtace Chemistry and AdsorpWan from Solution". and "Simplified Circuit Analysb: DigitaCAnalog Logic". He is also a coeditor of the mOnP graph series "Computers in Chemlsny and Insmrmentatian" and "Water Quality Handbook" and has been a member of the ediioriai board of AnalflicaI Chemistry, AnaWcaI LefterJ, Chemlcei Instrumentation and Talanta.
zymatic oxidation of these substances, Thus, the ahovementioned 2-hydroxy-1-naphthaldehyde thiosemicarhazonez/Mn(II) system allows as little as 50 pmol of H20zto e determined. The calibration graph is linear from 0.3 to 3.7 p M for cholesterol, 0.7 to 10 p M for L-amino acids, and 1.5 to 15 pM for linoleic acid. Cholesterol can he thus determined in egg yolk, cod liver oil, and horse serum with recoveries between 96.8% and 104.5% (98). The analyte can in some cases generate the catalyst or substrate involved in the indicator reaction. This idea suggested investigating the analytical potential of coupling amplification reactions with catalytic determinations (99). As amplication reactions usually involve iodine systems, reactions involving iodide are preferred. One way to simplify this approach, characterized by its high sensitivity, involves avoiding the amplification reaction by direct coupling the indicator reaction to that yielding iodine or iodide. This experimental approach gave good results in the determination of dichromate
6"
upon reaction with iodide hy use of the Ce(IV)-As(III) system and can he extended to a number of other substances. There are relatively few methods for the determination of nonmetals and organic compounds based on the catalytic effects of these species. One such method allows the determination of bromide ion at concentrations between 1and 40 ng/mL based on its catalytic action on the oxidation of iodine to iodate (100). Experimentally, the method involves adding potassium iodide and sulfuric acid to a sample containing less than 40 ng of Br-/mL and thermostating a t 10 "C. The oxidation reaction is started by adding potassium permanganate. Twelve minutes after the last reactant is added, unreacted iodine is extracted with CCl,, and this quantitatively hack-extracted into an aqueous phase as triiodide by shaking with exce65 potassium iodide. The absorbance of the aqueous phase is measured at 350 nm against water. The method can normally he applied to CI- determination a t the pg/mL level in samples such as rain, river, and well water. The catalytic effect of carbonate on the formation of the Cr(II1)Xhrome Azurol S complex at 35 "C in an acetate buffer of pH 5.0-5.2 was exploited for the determination of carhonates in alkali metal halides (KC1, CsI, and KBr) of special purity (101). The rate of absorbance change of the reaction mixture was monitored a t 595 nm for 10 min and found to he proportional to the Carbonate concentration in the range 0.5-10 pg/mL. The method of standard addition was used on account of the adverse influence of high concentrations of Cl-, Br-, and 1- on the indicator reaction. New applications of the iodine-azide system continue to appear. One such application was reported by Ramis-Ramos et al. (102),namely the enthalpimetric determination of sulfide and thiosulfate (detection limits 0.1 and 0.3 pg/mL, respectively) in the presence and absence of Zn(I1) and Cd(II), of which the former depresses the analytical response of sulfide, whereas the latter, surprisingly, enhances it. As the determination of sulfide involves a previous distillation whereupon H2S is retained by the Zn(I1) or Cd(I1) solution, the method allows the direct determination of sulfide in the resulting CdS suspension, thereby avoiding loss of the anion. In order to improve analytical methods based on the above-mentioned reaction, the iodine solution is slowly added at a known constant rate to the sample containing the divalent-sulfur compound and sodium azide. This operational mode allows a few nanograms of 2-thiouracils to he determined by the dead-stop technique (103). Other species such as sulfide, thiosulfate, thiocyanate, 6-mercaptopurine, cysteine, thiourea, ergothioneine, and glutathione have also been determined in this fashion a t the nanogram level by amperometry with two polarized electrodes (104). The same reaction was also used to develop a method for determination of cysteine, glutathione, and ascorbic acid in mixtures at the pg level by spectrophotometricmonitoring at 350 nm of the iodine consumed in the reaction (105). There are few literature references to the determination of organic compounds by redox reactions other than those involving the iodine-azide system. One of spectral interest is the determination of antipyrine (phenazone) on the basis of its catalytic effect on the oxidation of diphenylcarbazone by hydrogen peroxide (106). The decrease in the absorbance of dipheuylcarhazone at 490 nm up to within 45 s reaction time is proportional to the antipyrine concentration in the range 0.01-1 pg/mL. The authors applied the method to the determination of 3-53 pg/mL of antipyrine in 10-pL human ~. blood samples. The oxidation of hydriodic acid by Cr(V1) has heen found to he catalyzed hy 22'-hipyridyl. This reaction is the basis for a kinetic determination of microgram amounts of 2,2'bipyridyl (up to 32 wg/mL) and Cr(V1) (0.05-1.8 pg/mL) by monitoring, at 353 nm, the absorbance of the triiodide formed (107). Formaldehyde increases the rate of oxidation of p phenylenediamine by hydrogen peroxide. This is the foundation of a kinetic photometric method for the determination of formaldehyde by initial-rate measurement (108). The method is not very sensitive (linear range between 50 and 500 G/mL) but has acceptable reproducibility (relative standard deviation ca. 3%). According to its proponents, it could be applied to the determination of formaldehyde in air. Various tertiary amines (triethylamine, tripentylamine, Np-diethylaniline, and pyridine) can he determined a t the millimolar level through their selective catalytic effect on the ~~
ANALYTICAL CHEMISTRY, VOL. 60. NO. 12, JUNE 15. 1988
183R
KINETIC ASPECTS OF ANALYTICAL CHEMISTRY
Table 1. Determination of Different Catalytic Species by Kinetic Methods Based on Primary Effects
apecies cobalt
indicator reaction aerial oxidation of o-hydroxyphenylthiourea
5-50
aerial oxidation of 1,3-cyclopentadione bis(4-methylthiosemicarbazone) hydrochloride Pyrogallol Red + H202
50-400
Pyrogallol Red
+ H2O2
0.2-13.0 0.2-13.0
Alizarin Red + HzOz
5.9
stilbazo or cathecol
1
4,5-dihydroxy-1,3-benzene
0.003-5.0
aerial oxidation of
50-60
disulfonic acid (Tiron) + H202
copper
dynamic range or detection limit, ng/mL
N-phenyl-2-mercaptoacet-
or 150-1500
amide disulfide
aerial oxidation of hydroxylamine
0.6-50.8
morin + H202
15-50 or 150-500 (without H202)
hydrazine + H202
15-200 or 100-900
Variamine Blue + ammonium 6-660 persulfate oxidative coupling of N,N-dimethylaniline and
0.05-1.2
3-methyl-2-benzothiazoline
hydrazone by H202(NH, as activator) 1,1,3-tricyano-2-aminopropene 1-30
(TRIAP) + HZ02(in presence of imidazole)
184R
imidazole + H2O2
0.5-150
chromotropic acid + H202
12.7-191
ANALYTICAL CHEMISTRY, VOL. 60, NO. 12, JUNE 15, 1988
comments
type of sample
photometric monitoring of plant disulfide formed; initial-rate method photometric monitoring (380 nm); initial-rate method; Ni, Cu, Cr, Fe, V, and other ions interfere photometric monitoring (515 nm); fixed-time (5 min) method same as above pharmaceuticals (determination of vitamin BIZas cobalt photometric monitoring; flow injection system: 60 samples/ h photometric monitoring; flow injection system: 60 samples/ h improved air-segmented continuous-flow technique; many species interfere at 100-fold ratio to cobalt photometric monitoring (340 nm); alkaline medium and 80% (v/v) methanol and 1.4 M ammonia; gold(II1) inhibits copper catalysis; zinc and cadmium also interfere photometric monitoring of natural water (tap and lake) nitrite formed as azo dye; in alkaline medium the generation of nitrite is first-order in hydroxyl ions fluorometric monitoring of decreasing fluorescence of morin; fixed-time, variable-time, and initial rate methods; Be, Mn, Fe, and Ni interfere seriously thermometric monitoring; no wine (after sample interference from many mineralization) metal ions up to 20-fold Cu concentration; Fe(III), Pd, Mn, and Co interfere seriously photometric monitoring (540 nm); initial-rate method; 20% acetonitrile enhances catalytic activity of copper photometric monitoring (590 natural water (tap, river, sea) nm); fixed-time method; few interferences fluorometric monitoring of oxidation product of TRIAP; high selectivity; imidazole apparently required to stabilize Cu(I), the potential effective catalyst fluorometric stopped-flow using inexpensive home-designed equipment; method advantageous comparing with conventional kinetic or equilibrium methods; 60 samples/ h photometric monitoring (430 nm); few interferences
blood serum
ref 17
18
19 20 21 22
23
24
25
26
27
28
29
30
31
water (tap, sea); bovine liver standard
32
KINETIC ASPECTS OF ANALYTICAL CHEMISTRY
Table I (Continued)
species gold iodine
indicator reaction aerial oxidation of Variamine Blue Ce(1V) + As(II1)
dynamic range or detection limit, ng/mL 2-200
Ce(1V) + As(II1) Ce(1V) + As(II1) Ce(1V) + As(II1)
3
Ce(1V) + As(II1)
0.38
Ce(1V) + As(II1)
iridium
chlorpromazine + BrOf
5-10
periodate dissociation
192
Variamine Blue + IO, iron
Methylene Blue + IO4-
Rhodamine B + 02
140-1700
a-hydroxy acids + IO,
10-60
I- + BrO,
12-30
chromotropic acid + H202
11-168
3,5-diaminebenzoic acid hydrochloride + H202
1-12
comments
type of sample
ref
photometric monitoring; electrogilding washing baths highly selective method materials from cement results compared with those industry obtained by X-ray fluorescence analysis use of new procedure to avoid total iodine in foods (milk and loss of iodine dairy products), meat, potatoes, and cereals simpler and faster method to total iodine in urine and milk avoid loss of iodine; organic matter eliminated by alkaline ashing method involving separation inorganic iodide in plasma of iodide from organically bound iodide (ion chromatography); prior precipitation of plasma protein with ethanol and subsequent alkaline ashing fluorometric monitoring of Ce(II1) directly or of unreacted Ce(1V) via quinone formation with 8-quinolinol; two-line flow injection system saline water interfering mg quantities of C1- eluted from separation column by strong anion exchanger; retained Ieluted with 2 M ",NO3 photometric monitoring (525 iodinated salt and rate thiroid nm); initial-rate method monitoring of rate of oxygen evolution with Clark electrode; metals of the , platinum family and other transition elements enhance effect of Ir(II1) or Ir(1V) photometric monitoring (540 ores nm) photometric monitoring of brass and lead absorbance decrease; 1,lO-phenanthroline 88 activator; good selectivity; manganese, however, catalyses the reaction photochemical process; chemicals and blood serum photometric monitoring (557 nm) or fluorometric monitoring (excitation at 550 nm, emission at 577 nm) reaction promoted by Fe(1I) and induced by hecyanoferrate(11); potentiometric monitoring with periodate-selective electrode; mechanisms proposed for both effects reaction induced by Fe(I1) total iron in fresh water (tap, well, and sea) and Fe(II1); photometric flow-injection system photometric monitoring (440 tap and seawater; bovine liver nm); accurate, reproducible, standards and selective method photometric monitoring (540 tap water nm); rather selective method despite Cu(I1) interference; calcium interference circumvented by coprecipitating Fe(OH), and Mg(OH)2
ANALYTICAL CHEMISTRY, VOL. 60, NO. 12, JUNE 15, 1988
33 34 35 36
37
38
39
40 41
42 43
44
45
46 47 48
185 R
KINETIC ASPECTS OF ANALYTICAL CHEMISTRY
Table I (Continued)
species
indicator reaction
dynamic range or detection limit, ng/mL
iron
o-dianisidine + S202'
50-1500
lead
complexation of Mn(I1) by
0.02
5,10,15,20-tetrakis@-sulfo-
pheny1)porphine manganese
aerial oxidation of morin in alkaline medium
70
autoxidation of o-hydroxyphenylthiourea
50-500
oxidation of succinimide dioxime by dissolved O2 in basic medium
0.2-10
salicylaldehyde guanylhydrazone
8-80
+ H20z
sulfanilic acid + 101-
0.5-5
Methylene Green + IO4-
0.2-30
Malachite Green + IO;
0.1-10
+ 10,-
0.2-9
H,POp-
oxidative coupling of N,N-dimethylaniline and
2.0
3-methyl-2-benzothiazolino
hydrazone by dissolved oxygen
mercury
aerial oxidation of 2,2'-dipyridyl ketone
30-300
molybdenum
iodide + H202(in presence of ascorbic acid)
100
same as above
186R
type of sample
ref
wine and lemon leaves
49
rain and drain water
50
:omments
C
ANALYTICAL CHEMISTRY, VOL. 60, NO. 12, JUNE 15, 1988
photometric monitoring (450 nm); 1,lO-phenanthrolineas activator; fixed-time (5 min) method; not very selective photometric monitoring (413 nm); fixed-time (15 min) method; interference of cadmium overcome with cyanide fluorometric monitoring; initial rate method recommended photometric monitoring (416 nm); initial-rate and fixed-time methods; good selectivity and reproducibility; sensitivity improved by addition of ethylenediamine photometric monitoring (695 nm); flow injection system; sample injected in EDTA stream to avoid interferences; sampling rate: 45/h photometric monitoring (505 nm); initial-rate method; reasonably selective photometric monitoring (360 nm); initial-rate method; 1,lO-phenanthroline as activator improves sensitivity as well as selectivity photometric monitoring (620 nm); initial-rate method; rather selective but Fe(II1) interferes by catalyzing the reaction improved method using higher temperature (48 "C) and reagents concentration; induction period is eliminated; sensitivity (initial-rate) is 10-fold conventional method; no gain in selectivity photometric monitoring (236 nm); only cobalt interferes of 20 elements tested; nitrilotriacetic acid as activator photometric monitoring (590 nm); acceptable reproducibility but calibration curve nonlinear; few interferences, only Cu(I1) interferes at 20-fold concentrations; 1,lO-phenanthrolineadded as activator fluorometric monitoring; initial-rate method; poor selectivity and reproducibility; H202helps in the catalytic cycle Landolt reaction monitored conductometrically and potentiometrically sample mineralization and extraction
51 cabbage, potatoes, tomatoes
52
chemicals, coffee, rice
53
ores, cement, lead concentrates, basic slag
54 55
water, milk, beer
56
57
58
59
60
61 grass
62
KINETIC ASPECTS
OF ANALYTICAL CHEMISTRY
Table I (Continued)
species molybdenum
dynamic range or detection limit, ng/mL
indicator reaction same as above I- + H202
100
same as above
2
rubeanic acid + HzOz
100
niobium
ascorbic acid + H202
osmium
As(II1) + IO4-or IO; As(II1) + 103-
0.0005-5
palladium
EDTA-Co(II1) complex + HZPOT
80-555
ruthenium
p-(dimethy1amino)azobenzene 0.1-20
selenium
silver
+ IO,
p-ethoxychrysoidine + 101-
0.2-3.0
(N-methyldipheny1amine)sulfonic acid + IO,-
0.05-0.5
reduction of Methylene Blue by NazS
100-400
oxidation of EDTA-Fe(II1) complex by NaNO,
5-40
reduction of tetranitro blue tetrazolin by dithiothreitol in presence of Fe(III), which accelerates the reaction reduction of picrate by NazS
0.5-300
Pyrogallol Red + Sz082-
0.85-21
100-1000
comments
type of sample
ref
application of an earlier plant material method (Analyst (London) 1975,100, 1-6) biamperometric monitoring in soil extracts flow injection system under microprocessor control; sampling rate, 100/h detection limit improved by Simplex optimization photometric monitoring (390 plant materials nm) in 0.1-0.2 M HCl or 0.08 M HzS04 thermometric monitoring; pH products from titanium 3.6-3.8 at which optimum production catalysis from Nb is observed and Ti and Ta exeirt minimal catalytic effect Os04 is distilled and absorbed complex natural industrial in 0.10 M acetic acid or 1 samples mM KC1 measurement of induction standards and nickel mattes period; amperometric monitoring; very selective; main catalytic activity due to Os(VII1) photometric monitoring (547 hydrogenation catalysts nm); initial-rate method; interference from metal ions of the Pt family photometric monitoring (513 nm); initial-rate method; rather selective but Au(III), Ce(III), Ag(I), and Os(VII1) interfere photometric monitoring (477 nm); iodide activates the catalyzed reaction; highly selective method, Os(VII1) is tolerated in a 20001 molar ratio to Ru and other metal ions at least up to a 201 molar ratio photometric monitoring (490 ore-flotation tailings nm); fixed-time (16 min) method; very selective, only iridium interferes appreciably at Ru/Ir ratios below 1/25 fluorometric monitoring of water, biological and blue fluorescence of geological samples colorless form of dye; induction period measured photometric monitoring (440 biological samples nm); optimum pH 2, adjusted with H2S04; separation by ion-exchange chromatography prior to determination photometric monitoring (600 nm) of reduction product; very selective photometric monitoring (470 nm); flow injection system; interferences removed by precolumn cation exchange and masking with EDTA photometric monitoring of absorbance decrease (471 nm); poor selectivity
ANALYTICAL CHEMISTRY, VOL. 60, NO. 12, JUNE 15, 1988
63 64
65 66 67
68 69
70
71
72
73
74
75
76
77
78
187R
KINETIC ASPECTS OF ANALYTICAL CHEMISTRY
Table I (Continued)
species silver
dynamic range or detection limit, ng/mL
indicator reaction pyrocathecol 1-aldehyde 2-pyridylhydrazone + s20:-
10-80 or 200-800 (without activator)
Xylenol Orange + S2082-in presence of 2,2'-bipyridyl
0.3
disodium
1.3-76 and 76-130
2-( 1H-l,2,4-triazolyl-3-azo)-
technetium tungsten and vanadium
vanadium
1,8-dihydroxynaphthalene3,6-disulfonate + S202reduction of 50-2500 tetrahydroxy-l,4-benzoquinone by Sn(I1) 2,4-diaminophenol + HzOz W: 463-73500 V: 20-2500
chlorpromazine hydrochloride 10-400 + BrO; oxidative coupling of 0.1-1.0 NJ-dimethylaniline and 4-aminoantipyrine by BrOsI- BrO; 100
+
CI Mordant Blue + Br0c gallic acid + BrO;
2.5-25
same as above
2.5 (lowest determined concn) 10-500
o-phenylenediamine
+ BrOs-
cyclic condensation of malonic acid with acetic anhydride in nonaqueous media (109). The method, implemented in a flow injection system, uses fluorometric detection.
KINETIC METHODS BASED O N INHIBITION OR ACTIVATION OF CATALYSIS This section reviews methods based on modified catalytic reaction rates. Such methods can be implemented by addition of activating or inhibitory substances, which increase or decrease the reaction rate. Both effects can be exploited to develop methods for determination of species normally not exhibitin catalytic properties. In addition, the use of activators su!kantially im roves the sensitivity of catalyst determinations. Occasiody, the activator is added as a complex with the catalyst, as is the case with alkaline tartrate solutions of Nb(V) (110),which can be used as standards in the catalytic determination of N b based on the catalytic action of this species in the Hz02oxidation of ascorbic acid. Methods for the determination of catalysts based on the presence of an activator were included in the previous section. On the other 188R
ANALYTICAL CHEMISTRY, VOL. BO, NO. 12, JUNE 15, 1988
type of sample
comments
ref
fluorometric monitoring with poor selectivity; lJ0-phenanthroline used as activator photometric monitoring (441 nm): temperature, 24-36 OC; pH, 4.3-5.1 alkaline medium (pH 8.4), photographic film a,d-bipyridyl as activator
79
photometric monitoring (615 nm); tin(I1) needed to observe Tc catalysis acid medium; photometric monitoring (500 nm); different catalytic activity under different experimental conditions photometric monitoring (526 nm); 2 M H,PO, medium; rather selective, iron and nickel do not interfere photometric monitoring (555 nm); applicable to V(V) and V(1V); very selective Landolt reaction in presence of ascorbic acid; conductometric monitoring, induction period ratios (in absence and in presence of vanadium) used for calibration graphs photometric monitoring (510 nm); reaction in perchlorate medium thermometric monitoring improves selectivity and precision of conventional photometric method while retaining sensitivity photometric monitoring (380 nm); flow injection system, 12 samples/h photometric monitoring (440 nm); flow injection system; optimum pH, 3.0; pH and injection volume (0.18 mL) are critical variables; interfering Fe(II1) reduced with 0.3% NHIF aa carrier; sampling rate, 60-70 per h
82
plants
80 81
83
petroleum products
84
tap, river, and seawater
85 86
untreated urine; mineral water
87
steel
88
89 pond and river water
90
hand, inhibitors are mainly used in catalytic titrations. Relatively few determinations based on the use of activators, or promoters, and inhibitors were reported over the last two years. Activation. Two methods have been proposed for the determination of metal ions based on their activating effect on enzymatic reactions. Thus, vanadium(V) activates the oxidase-catalyzed oxidation of NADH in the presence of xanthine, dithiothreitol, and silver. Ghe e t al. (111) determined V(V) in the 200-500 ng/mL range by an initial-rate procedure based on this activating effect. An automated photometric method for determination of magnesium has also been reported (112). In this method, the Mg-dependent enzyme glycerol kinase is used t o catalyze the phosphorilation of glycerol t o glycerol-3-phosphate, the latter being oxidized to dihydroxyacetone phosphate and HzOzwith glycerol-3phosphate oxidase. The hydrogen peroxide is reacted with 4-aminoantipyrine in the presence of peroxidase and 3,5-dichloro-2-hydroxybenzenesulfonateto produce a red product for which absorption is monitored at 510 nm. The calibration graph prepared by plotting the rate of change of absorbance
KINETIC ASPECTS OF ANALYTICAL CHEMISTRY
a ainst the magnesium concentration is linear up to 2 mM. interference from bilirubin up to 200 pg/mL or calcium ion up to 5 mM was observed. Although the activating effect of organic ligands is commoner than that of metal ions, only two methods for such determination of or anic compounds have been reported in the last two years. oncentrations between 0.15 and 3.1 HM of ascorbic acid, one of the lowest levels achieved for this species, can be determination by exploiting its activating effect on the oxidation of 2-hydroxy-1-naphthaldehydethiosemicarbazone by oxygen (manganese as catalyst) in a basic medium (113). The reaction is monitored fluorometrically and yields best results by initial-rate measurements. The method is selective and allows the determination of ascorbic acid in various pharmaceuticals and fruit juices as well as ascorbic and dehydroascorbic acid in urine, with no sample pretreatment. Papaverine accelerates the decomposition of HzOzby Co(p), probably as a result of the formation of a catalytically active 1:1 complex with cobalt. This is the basis for an initial-rate method proposed by Milovanovic and Sekheta (114) for the determination (photometric monitoring at 510 nm) of papaverine at concentrations between l and 12 pg/mL. The method is rather selective and permits the determination of the alkaloid in samples of urine with good results. Inhibition. Inhibitory effects have been used mainly to obtain thermodynamic data. Thus, the reaction between iodine and azide, catalyzed by sulfur compounds, is the basis for a catalytic thermometric method for calculation of the stoichiometry and formation constants of complexes formed between sulfur-containing ligands and metal ions acting as inhibitors (115). The proponents applied the method to the Ni(I1)-1-pyrrolidinedithiocarbamate and Ni(I1)-diethylthiocarbamate complexes and improved their experimental design by thoroughly studying the error associated with the method. The inhibitory effect of Pd(I1) on the iodine-catalyzed reaction between Ce(1V) and As(II1) was used for the determination of cerium in the 5-20 ng/mL range with thermometric monitoring (116). The method was applied to the determination of palladium in active carbon samples. Mercury(I1) can be determined in water and carbonated soft drinks in the 100-270 pg mL range and without need for preconcentration by its inhi ition of 1-fructofuranosidase in the hydrolysis of sucrose (117). The method requires, however, destruction of organic matter and isolation of mercury to avoid interferences. A special type of inhibition called “counter-inhibition” is the basis for a method for determination of iron(II1) involving reversed flow injection analysis (118), which is also used for EDTA determination. Both determinations are based on the effect of these species on the Cu(I1)-catalyzed oxidation of di-2-pyridyl ketone hydrazone by hydro en peroxide. The inhibitory effect of EDTA is increased y the presence of Fe(II1) which forms a complex more stable than that of Cu(I1). This allows the indirect determination of Fe(II1) with good reproducibility but poor selectivity. Phosphate can be determined at concentrations between 10 and 140 ng/mL by its inhibitory effect on the Fe(II1)catalyzed oxidation of N,N‘-diethyl-p-phenylenediamine by HzOz, by monitoring the reaction rate at 515 nm, and by applying the differential tan ent method to calculate the phosphate concentration (1198. Unfortunately the method is neither precise nor selective.
80
e
I:
t
TITRIMETRIC METHODS WITH CATALYTIC END-POINT INDICATION New theoretical and experimental approaches and unusual applications to the determination of species in mixtures have been developed in the field of titrations with catalytic endpoint indication in the last two years. A new contribution to the theory of titration curves of this type was made by Gail et al. (120)with a study of the titration of strong acids and bases. The influence of various factors on the shape of simulated curves was discussed and treated by an appropriate mathematical model taking into account the autoprotolysis of the solvent. The expressions derived can also been used to simulate titration curves for weak acids and bases under given conditions. Most of the procedures reviewed used catalytic titrants, which react rapidly and stoichiometrically with the species
of interest, and an indicator reaction involving the monitored species and occurring at an appreciable rate only when the titrant is in excess. A novel catalytic titration mode called “titration by substrate inactivation” has been, however, reported (121). In this approach, the analyte instead of inhibiting the catalyst inactivates one of the reactants (the titrant). The titration is carried out in presence of the other components of the indicator reaction as well as the catalyst, which acts on this reaction only after the analyte has been fully titrated. The approach is applicable provided that the titrant forms a stable compound with the analyte. Such is the case with the determination of Hg(I1) with the 4,4’-dihydroxybenzophenone thiosemicarbazone HzOz Cu(I1) system. The combination of the catalytic e fect o Cu(I1) and the inhibitory effect of Hg(II), along with the blocking of the catalytic cycle by EDTA, are the basis for a titrimetric method for individual as well as simultaneous determination of H and Cu or Cd in the ranges lo-’ to lo4 M for Hg(I1) and 10 to M for Cu(I1) or Cd(I1). Copper/mercury and cadmium/mercury mixtures can be resolved in the molar ranges of 20.1-4.1 and 27.1-1.1, respectively (121). By use of the above system but application of the traditional approach, EGTA can be determined at the micromolar level in mixtures with EDTA or NTA (122). The method is based on the addition of excess Mg(I1) to a sample aliquot in which only EGTA is titrated while both ligands are titrated in a separate aliquot. The same system also allows the individual titration of NTA. The iodide-catalyzed hydrolysis of hexachloroantimonate(V) is inhibited by silver(I), which can thus be determined in pharmaceutical preparations of silver-sulfathiazine by titration with iodide. The samples need to be treated to ensure complete dissolution of silver. The titration curves are obtained by plotting the change in absorbance at 270 nm as a function of titrant (iodide) added (123). The same system and operational mode were used to determine mercury in calomel samples and ear-eye drops with satisfactory results (124). A determination of aminopolycarboxylic acids (EDTA, EGTA, DCTA, and DTPA) with Mn(I1) as catalytic titrant and the periodate/diethylaniline indicator system was developed to demonstrate the usefulness of flow-injection ”pseudotitrations” in catalytic end-point indication (125). A completely automated spectrophotometric system was used; the authors claim that the peak width in time units is simpler and more precise than graphical end-point location and illustrates the kinetic view of flow-injection “pseudotitrations”. Few catalytic titration methods with fluorometric end-point detection were reported in the last couple of years. A new contribution in this respect is represented by the semiautomatic titration of cyclohexane-l,2-diaminetetraacetic acid and the indirect titration of Ni(I1) and Mn(I1) at the pg/mL level with an uncertainty of about 1.5% (126). The determination involves the Mn(I1)-catalyzed reaction between 2-hydroxybenzaldehyde thiosemicarbazone and hydrogen peroxide. The possibility of applying conductometry to catalytic end-point indication of neutralization titrations was investigated by Gail et al. (127). Both conductometric and highfrequency conductometric methods were used for the titration of sodium acetate using the acetic anhydride/methanol system or formic acid as indicator, with volumetric or coulometric addition of a strong acid. Using conductometric indication, the authors succeeded in determining sodium acetate at the microgram level. By use of the exothermic dimerization of acetone catalyzed by hydroxyl ions, some sulfonamides (e.g. sulfathiazole, sulfamerazine, and sulfamethoxazole) can be titrated thermometrically a t the milligram level (128). The sulfonamides exhibit acid properties and can be titrated in an acetone medium with either volumetric or coulometric addition of hydroxyl ion. The end point is more accurately determined from the coulometric titration curves which exhibit better defined shapes. Barbitone and phenobarbitone can be titrated by a nonaqueous catalytic thermometric method. The sample (about 1.0 mg) is dissolved in 1:l acrylonitrile/DMF and is titrated with a solution of KOH in 2-propanol (129). The temperature change at end-point is sharper for barbitone than for phenobarbitone. Catalytic end-point indication has also been used to study the reactivity of systems such as vinyl and vinylidene mo-
4fi
3
ANALYTICAL CHEMISTRY, VOL. 60, NO. 12, JUNE 15, 1988
189R
KINETIC ASPECTS OF ANALYTICAL CHEMISTRY
nomers used as thermometric indicators. Thus, a wide range of monomers can be screened rapidly for their ability to undergo polymerization at room temperature upon treatment with strongly acidic or basic catalytic titrants. The increase in temperature occurring after the initiation of the polymerization reaction-whether cationic or anionic-is a measure of the monomer reactivity (130).
KINETICS AND MECHANISMS OF SOME CATALYZED REACTIONS OF ANALYTICAL INTEREST It is worth commenting here on the advances in the study of the kinetics and mechanisms of catalyzed reactions of analytical interest as these will contribute to improve existing methods and develop new ones based on them. The displacement of certain coordinated ligands from their complexes is considerably facilitated by the addition of some metal ions. Thus, the metal-ion-catalyzed aquation of transition-metal complexes was reviewed by Banrerjee (131),who dealt with the rate law, the formation of adducts, and the catalytic efficiency and nature of the activated complexes and their application to chemical analysis. The kinetics and mechanism of the iodine-azide reaction have been used to illustrate a videotaped student experiment (132). This was carried out with carbon disulfide as catalyst and starch solution permitting detection of a sudden blueblack to colorless end point. From two sets of experiments, the fractional order and activation energy can be calculated. Other experiments show that the reaction between iodine and the transient disulfide-azide complex, S2CN3-,is quite fast. The Ce(1V)-As(II1) System. A study on the Cr(II1)catalyzed oxidation of As(II1) by Ce(1V) in aqueous sulfuric acid was recently reported (133). Chromium(1V) was shown to be involved in the catalyzed pathway. Again, this reaction involves the catalyst and only one of the reactants in the rate expression. Increasing sulfuric acid concentrations result in enhanced catalyzed and uncatalyzed reaction rates. The species H3Ce(S04)4-is believed to be the effective oxidant. Decomposition of H202. The catalytic decomposition of hydrogen peroxide by dichromate was recently used as the basis for a very simple student laboratory experiment for determining the rate of the reaction (134). When the dilute solutions of Crz072-and H,02 were mixed, the orange color of the former changes to brown and oxygen evolution starts. Once the reaction is complete, the color of the solution changes back to orange. If more peroxide is added a t this point, the same sequence of events is observed again. The brown color is indicative of the chemical interaction between the catalyst and H202. The experiment finally involves measuring the catalyst regeneration at the end of the reaction by monitoring absorbance at 350 nm. New contributions to understanding the kinetics and mechanism of decomposition of hydrogen peroxide by aminopolycarboxylate complexes as catalysts have been reported (135). The results obtained were consistent with substitution-controlled mechanisms involving the formation of ternary peroxo complexes. Such are the cases with the decomposition of HzOz by the ethylenediaminetetraceto-Ce(1V) and ethylenediaminetetra(methy1enephosphonate)-Mn(I1)complexes (136). The mechanism of the latter involves Mn(IV), as demonstrated by cyclic voltammetry and spectral measurements. In both cases, rate laws and consistent mechanisms were proposed. Ternary complexes of Cu(I1) with aromatic heterocyclic bases such as 2,2'-bipyridine and phenanthroline and optically active cy-amino acids such as S-prolinate also catalyze the polarographically monitored decomposition of hydrogen peroxide in aqueous media (133, for which different reaction mechanisms were proposed. System of Biological Interest. It is widely acknowledged that trace amounts of transition-metal ions such as Cu(II), Mn(II), and Fe(II1) are often decisively involved in a host of biological activities. In addition, the catalytic action of these metals on the oxidation and oxygenation of organic substrates by atmospheric oxygen is a subject of current interest. Thus, D-fructose is liable to induce photochemical oxidation by atmospheric O2to yield D-erythrose in the presence of iron or manganese as catalysts in neutral to weakly acid media (138). This reaction has been shown to proceed via a coupling with a redox cycle involving a metal ion, i.e. the photooxidation 190R
ANALYTICAL CHEMISTRY, VOL 60, NO. 12, JUNE 15, 1988
of D-fructose by Mn(II1) and the subsequent reoxidation of the resultant Mn(I1) by atmospheric oxygen. Sulfur-containing organic substrates are of special significance to biological processes, as acknowledged in some papers appearing in the past two years. Cysteine in proteins and glutathione are the major amino acids involved in vivo sulfhydryl redox reactions. As is widely known, the metal-catalyzed oxidation of sulfhydryl compounds yields hydrogen peroxide, which has been shown to occur in the aerial oxidation of glutathione in the presence of Fe(I1) or Cu(II), the mechanism of which involves a glutathione-metal complex and dissolved oxygen (139). In this reaction, catalase can completely prevent the buildup of detectable Hz02,whereas superoxide dismutase is only slightly inhibitory and hydroxyl radicals and singlet oxygen quenching agents (e.g. mannitol and histidine) are stimulants. On the other hand, silver and gold inhibit the selenium-accelerated oxidation of cysteine by atmospheric oxygen. The interaction between selenocystine and sodium selenite with metal ions and the effect of gold ligands on the inhibition of this reaction by Au(1) were investigated by the same authors (140). Reactions Catalyzed by Transition-Metal Ions. The effect of Mn(I1) on synthetic organic substances bearing thiol groups has been shown to be similar to that exerted by Cu(I1) or Fe(I1) on glutathione. Thus, in the Mn(I1)-catalyzed oxidation of 2-hydroxynaphthaldehyde thiosemicarbazone by hydrogen peroxide, the latter is regenerated as a result of the production of superoxide ions; Mn(II1) appears to be the active form of the metal (141). The proposed mechanism involves the formation of a complex between the organic compound and manganese. Likewise, the catalytic action of Fe(II1) on the well-known oxidation of 2,4-diaminophenol by HT02is explained on the basis of the formation of a mixed-ligand catalyst-substrate oxidant complex, the occurrence of which is confiimed by the obtainment of the maximum reaction rate at the theoretically calculated pH (142). Both differential and integral methods have been used for the calculation of the rate coefficient of the Co(I1)-catalyzed oxidation of Pyrogallol Red by H,Oz in a borate buffer of pH 8.0-8.7 in order to propose a kinetic model for the system (143). Borate decreases the initial rate, possibly as a result of the ability of cobalt to complex with borate. A kinetic photometric study was carried out by the authors at 415 nm, the wavelength of maximum absorbance of the suspected oxidation product, a semiquinone radical. The oxidative carbonylation of primary and secondary amines by bubbling of O2 and CO through the solution in the presence of the bis(salicyla1dehyde)ethylenediimine-Co(11) complex as catalyst has been studied and the sequence of reactivity from primary amines has been given (144). Proof of the catalytic role of the Co(I1) complex in these reactions was obtained by repeated addition of fresh substrate to a reacting mixture during the oxidative carbonylation at atmospheric pressure. The kinetics and mechanism of other reactions of interest involving catalysis by a Co(I1) chelate have been studied (145). Thus, the Co(I1) complex with acetylacetone catalyzes the oxidation of 3,5-di-tert-butylcatechol (3,5-DtBC) by atmospheric oxygen at room temperature in nonaqueous media. The only oxidation product is the corresponding o-benzoquinone (3,5-DtBQ). The reaction rate is first order in the Co(I1) complex, substrate, and partial pressure of molecular oxygen. The mechanism seemingly involves the reaction of the Co(II)(a~etylacetonate)~-3,5-DtBC complex with O2to give a ternary 3,5-DtBC-Co"-O2 complex and the intramolecular reaction of the ternary oxygenated cobalt complex to give 3,5-DtBQ in the rate-determining step. The kinetics of the catalytic action of Co(I1) on substitution reactions involving the Co(II1)-EDTA complex has also been studied (146). The rate of substitution of this complex by ethylenediamine (en) is considerably increased by the presence of excess Go2+in solution. The mechanism of the reaction is discussed by the authors on the basis of the Marcus theory for outer-sphere processes for electrostatic effects, considering ossible formation of a binuclear intermediate the (en)2 OI~I-EDTA-CO~I complex. Goyal and Saxena have studied the kinetics and mechanism of the Cu(I1)-catalyzed oxidation of formic acid by peroxydisulfate ion (147) and shown it to conform to a free radical mechanism. The attacking radicals are readily generated from the Cu(I1) complex of formic acid. The same authors have
e
KINETIC ASPECTS OF ANALYTICAL CHEMISTRY
also reported on the kinetics and mechanism of the Cu(I1)catalyzed oxidative decarboxylation of acetic acid by S201(I&), on which they obtain results similar to those found for formic acid. Grases et al. have studied the kinetics and mechanism of the Cu(I1)-catalyzed oxidation of o-dianisidine and related compounds (149)and diphenylamine (150)by technetium(VII). Their observations support the hypothesis that the catalyst action results from the ability of Cu(I1) to bind to the organic species concerned. Copper(I1) undergoes ready reduction to Cu(1) by SZ032in aqueous solutions. This reaction induces the reduction of tris(oxalato)cobaltate(III). The initial rate of the induced reaction is proportional to the initial concentration of Co(C 0 133- and Co(I1) and inversely proportional to that of SZb$- (151). The authors propose a reaction mechanism consistent with their observations. The basic hydrolysis of copper-methylenediaminemonoacetate is estimated to be lo4times as fast as that of the free ligand. This is the basis for the kinetics and mechanism of the Cu(I1)-promoted hydrolysis of the methyl ethylenediaminemonoacetate, in which the methoxycarbonyl group is bonded to copper (152). The catalytic activity of ethylenebridged amino acid-Cu(I1) complexes on the dismutation of superoxide ion varies with the particular amino acid. Leucine, isoleucine, valine, alanine, glycine, and 2-methylalanine, for example, show marked differences in their ability to quench superoxides, an explanation for which is provided by the authors (153). Suh et al. (154)have studied the kinetics and mechanism of the Cu(II)- and Zn(I1)-catalyzedhydrolysis of acetylpyridine ketoxime pyridinecarboxylates and obtained results indicating that the two mechanisms proposed are comparably efficient in explaining the reactivity of the metal-substrate complexes involved. Reactions Catalyzed by Noble Metals. Silver(1) is known to be a suitable catalyst for oxidations with peroxydisulfate in weakly acidic media. Two contributions involving the use of acetate buffers were reported in the past two years. One used phosphite as reductant and led to the conclusion that Ag(1) exerts its catalytic effect through the formation of a complex between peroxydisulfate and Ag(II) or Ag(II1) (155). The reaction features a complicated hydrogen ion dependence and the rate coefficients calculated by the authors at different pH agreed with those obtained experimentally. The other contribution describes the kinetics and mechanism of the uncatalyzed and Ag(1)-catal zed oxidation of hydroxylamine by peroxydisulfate (156). {n this case, the Ag(1)-catalyzed reaction takes place via a 12-step mechanism and the role of Af” is beyond mere complexing with peroxydisulfate or acid. T is is the first redox reaction involving decomposition of peroxydisulfate. According to the authors, the rates calculated from known equilibrium constant values and determined rate coefficients were in fair agreement with experimentally observed rates. The behavior of potassium hexachloroosmate in neutral and alkaline media in dilute solutions typically used in kinetic methods (between lo-’ and lo4 M)has been studied with the aim of clarifying its catalytic efficiency (157).The results show that an Os(V1) compound with chlorine completely displaced in the inner sphere, Os02(OH)4“,is formed in alkaline media (pH B11.3). Such a compound has considerable catalytic activity that can be exploited for analytical purposes. Osmium(V1) also seems to participate in the oxidation of benzylphenylglycolic acid (and four other glycolic acid derivatives) by alkaline hexacyanoferrate(II1) catalyzed by Os04 (158). The mechanism involves the formation of an intermediate complex between the acid anion and Os(VII1) which rapidly decomposes to deoxybenzoin and Os(V1). Osmium(VII1) is regenerated by a fast reaction between Os(V1) and hexacyanoferrate( 111). Khomutova and Khvorostukhina have studied the kinetics and mechanism of the simultaneous catalytic action of osmium and generated iodine on the oxidation of As(II1) by periodate or iodate ions (159). Osmium(VII1)-or Os(V1)-and iodine are alternately reduced and oxidized via a reaction with As(II1) and periodate during an induction period of the indicator reaction. This process ceases when the arsenate has been consumed and iodine begins to build up. Osmium catalyzes the reaction only during the induction period. The catalytic
action decreases in the order Os > 12 > I-. The reciprocal of the induction period is linearly related to the sum of the concentrations of osmium and iodine in the reaction mixture and the data obtained can be used in optimizing conditions for the kinetic determination of traces of osmium. The kinetics of the Ru(II1)-catalyzed oxidation of primary, secondary, and tertiary amino alcohols by Ce(IV) in a sulfuric acid medium has been studied spectrophotometrically by Awasthi and Upadhyay (160).The reaction is zero order in oxidant and first order in sulfuric acid for primary amino alcohols. The same kinetic dependence in the oxidant and ruthenium was observed in the Ru(V1)-catalyzed oxidation of sodium salts of lactic, tartaric, and glycolic acids by alkaline hexacyanoferrate(II1) (161).Again, the oxidation proceeds via the formation of a complex between the substrate and ruthenium(VI), according to the mechanism proposed by the authors. The formation of a complex between sugars and Ru(II1) is the basis for the catalytic effect of this metal on the oxidation of aldoses by N-bromosuccinimide (NBS) in aqueous acetic acid (162). The order of reactivity of different aldoses investigated by the authors was D-arabinose > D-xylose > Dgalactose > D-mannose > D-glucose. In the proposed mechanism, the Ru(III)-substrate complex slowly reacts with NBS in the rate-determining step. Similarly, Ru(II1) and Ru(II1)-aminopolycarboxylic acid chelates catalyze the oxidation of ascorbic acid by molecular oxygen in the 1.5-2.8 pH range (163).The stability and catalytic activity of Ru(II1) chelates are inversely proportional. Hence, the activity of this metal ion and some of its chelates increases in the order Ru(II1)EDTA < Ru(II1)-iminodiacetate < Ru(II1). The tris(2,2’bipyridine)ruthenium(II) complex catalyzes the photochemical ligand substitution of carbonato-bis(ethy1enediamine)cobalt(II1) and bis(ethy1enediamine)oxalato-cobalt(II1) complexes by ethylenediamine (164).The mechanism proposed by the authors is extended to (bidentato-0,0 and 0,N)bis(ethylenediamine)-cobalt(II1) complexes. The catalytic activity of the excited triplet state, [R~(2,2’-bipyridine)~]]~+, can be increased for the ligand substitution of the glycinato ligand in bis(ethy1enediamine)(glycinato)cobalt(III) by ethylenediamine, which does not proceed at room temperature when the optically active isomer of [R~(2,2’-bipyridine)~]~+ and circularly polarized light are used. The oxidation of ketones by use of iridium as a homogeneous catalyst proceeds via a ‘mechanism which is unclear. Manibala et al. (165)carried out a kinetic study of the oxidation of 2-propanone by hexacyanoferrate(II1) in aqueous alkaline media in the presence of IrC13as catalyst, from which the authors concluded that an activated complex between the substrate and Ir(II1) and are the only reactive species involving iridium. Reactions Catalyzed by Other Species. Two papers concerned with the catalytic activity of technetium were reported in the past two years. They dealt with the Tc(VII)-catalyzed reduction of 1-amino-4-hydroxyanthraquinone (166)and Methylene Blue (167)by Sn(I1). Technetium(V) seems to be involved in both reactions on account of its ability to bind to both reagents to form intermediate complexes. Alkali-metal ions such as K+ and Na+ bound to 18-crown-6 bearing a thiazolium ion have been found to increase the rate of the oxidative decarboxylation of pyruvic acid in ethanol (168).This enhancing effect is accounted for by assuming the metal cation bound to the crown cavity and able to attract the pyruvate anions to the vicinity of the catalytic site. The chloride-catalyzed oxidation of arginine by chloramine-?‘ in a perchloric acid medium has been found to involve different reactive species of the oxidant and C1+ in the rate-determining step (169).Consequently, chloride-catalyzed oxidations proceed through kinetic paths different from those of the uncatalyzed reactions.
KINETIC DETERMINATIONS BASED ON ELECTRODE REACTIONS AND PROCESSES The increased use of electrochemical detection in flow systems has introduced another avenue through which measurements under dynamic conditions are rooted in analytical methodologies. Since the main dynamic component in such detection is the imposed flow conditions, they are not discussed in detail in this part of the review. They are surely covered in detail in the reviews on chromatography and ANALYTICAL CHEMISTRY, VOL. 60, NO. 12, JUNE 15, 1988
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electroanalytical determinations. The use of chemically modified electrodes is another area in which the increasing role of electrocatalysis is emphasized in contemporary analytical practices ( 170). Enzymatic electrocatalysis is to be singled out for its potential in the development of so-called biosensors. Interesting studies on enzymatic electrocatalysis have been reported by Bourdillon et al. ( 171). They demonstrated the efficiency of coupling enzymatic catalysis and electrochemical regeneration when the enzyme is covalently attached to the electrode surface. Heuser and Girard (1 72) discuss the electrocatalytic effect for transition-metal ions and applied it to enhance electrochemical detection in ion chromatography. Minimum detectable quantities of 0.3 ng and 3 ng for cobalt(I1) and manganese(II), respectively, are reported. Recycling between oxidation states two and three of the metal ions is considered responsible for amplification. Carbon paste electrodes chemically modified by admixing of cobalt phthalocyanine show electrocatalytic response toward oxalic and some a-keto acids (173). These species show clearly defined anodic peaks between +0.75 and 0.90 V vs Ag/AgCl, lower potentials than those observed at unmodified electrodes. The observed catalytic currents are independent of mass transfer, which allows the use of electrodes of relatively large surface area. Their studies involved reticulated vitreous carbon electrodes with chemically bonded (via carbodiimide coupling) glucose oxidase and the benzoquinone/hydroquinone couple as cosubstrate. A ferrocene-modified platinum electrode has been proposed for the voltammetric determination of ascorbic acid (at the M level) based on its electrocatalytic oxidation (174). Application is illustated with the determination of ascorbic acid in fresh fruit juices. An electrocatalytic cycle involving vitamin BIZhas been used by Rusling et al. (175), in conjunction with square wave voltammetry, to estimate total ethylene dihalides in unleaded and leaded gasoline. Reduction of vicinal alkylene dibromides takes place at a glassy carbon electrode in isooctane/water emulsions stabilized by Aerosol-OT and tetraethylammonium perchlorate. Detection based on catalytic polarographic waves has remained of interest in the analytical literature. Kakizaki et al. have used it for the determination of catecholamines after high performance liquid chromatographic separation (176). Perchlorate ions exhibit a catalytic polarographic prewave in the presence of molybdenum(V1) and in 0.10 M hydrochloric acid medium. This permits determination of C104- with a limit of detection at the 2 X M level, at 40 "C (177). Cobalt in metallic nickel and in nickel salts has been determined by means of the catalytic polarographic current developed in a nitrite system (178). The presence of Ni(I1) in an ammonia buffer of pH 9.3 allows determination of cobalt at the M concentration level and improves the selectivity of the determination. Vanillylmandelic acid (3-methoxy-4hydroxymandelic acid) in the 2.5-35 ng/mL range has been determined in a flow injection system with electrochemical detection of the polarographic catalytic wave developed in a molybdenum(V1)-bromate ion system ( 1 79). The continuous-flow system incorporates a device for continuous removal of dissolved oxygen and allows the processing of 100 determinations per hour. One of the lowest limits of detection reported for vanadium (about 7.5 X M) is realized by use of the catalytic wave of the vanadium(1V)-pyrocatechol complex in the presence of bromate and pulse polarography (180). This limit of detection compares the determination with anodic stripping. Tungsten(V1) and molybdenum(VI), however, interfere seriously. Experimental studies on some homogeneous catalytic systems consisting of an oxidant and a metal ion in the form of a complex (e.g. Br03- and a group of Fe(II1) or V(1V) complexes, NO, and Co(II), V(IV), or Cr(II1) complexes, and Ti(1V)-oxalate in presence of C103-) have been reported by Zarebski (181). His differential pulse polarographic studies have led him to conclude that determinations involving catalysis are 1to 2 orders of magnitude more sensitive than those where no catalytic effect takes place. Such observation applies to the direct determination of metal ion catalysts as well as to the indirect determination of some oxidants. Iron has been determined by differential pulse polarography using the catalytic wave exhibited by its complex with N-(2-hydroxyethy1)ethylenediamine-N,N',N'-triacetic acid (HEDTA) in 192R
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presence of bromate and in Britton-Robinson buffers (182). The catalytic current is pH dependent, showing a maximum a t pH 3.7, but decreasing rather sharply a t higher or lower pH values. The limit of detection is reported as 5.2 x M. The method has been applied to the determination of iron in fresh snow and rain waters. A catalytic prewave appears in solutions containing cobalt(II), Tris-HC1, and the perchlorate of 5,5-dimethyl-1,3cyclohexanedione dithiosemicarbazone (DYDT). This prewave has been studied for the determination of DYDT, Hg(II), and Ag(1) (183). Banicka (184)has studied the catalytic nickel prewave produced in the presence of cysteine-containing dipeptides in acetate buffers of pH 4 to 6.5. The wave obtained a t pH 4.8 permits the determination of the cysteinyl-phenylalanine and the cysteinyl-tyrosine dipeptides in the lo4 to M range in the presence of the constituent amino acids.
APPLICATIONS OF CHEMI- AND BIOLUMINESCENCE The popularity of chemi- and bioluminescence has remained a t about the same level as in the two years covered in the previous review in this series ( I ) . The low limits of detection aforded by these approaches and the ease of their adaptation to continuous-flow systems are the two main attractions for practicing analysts. A summary of selected methods of determination by these luminescence techniques is given in Table 11. Amplification of the luminescence from the lucigenin-Hz02 reaction using membrane-mimetic agents has been reported by Riehl et al. (205). In a subsequent paper the same authors report on the improved determination of hydrogen peroxide or lucigenin by use of organized assemblies (206). A study of the xanthine oxidase initiated luminol chemiluminescence with implications on chemiluminescence measurements has been described by Wilhelm and Vilim (207). The catalytic effect of ferritins with different iron contents on the oxidation of luminol by hydrogen peroxide has been studied by Henley and Worwood (208). Iron-rich ferritins are less catalytic and ferritins with iron/protein ratios of less than 0.1 are the best catalyts. The luminescence uantum yield of ytterbium(II1) complexes with mono- an! bisazo dyes is increased 2 to 7 times by addition of 1,lO-phenanthroline and formation of a mixed-ligand complex (209). KINETIC METHODS BASED ON UNCATALYZED REACTIONS Cummings and Pardue (210) studied the kinetics of the reaction between cyanide and methemoglobin and developed a fast kinetic method for methemoglobin determination. The method was also used for the determination of hemoglobin in whole blood after reaction with hexacyanoferrate(III),which produces methemoglobin. The measurement approach entails monitoring of absorbance (630 nm) as a function of time and a curve-fitting data treatment. Stopped-flow mixing provides more reliable mixing conditions but centrifugal mixing can be used by slowing down the reaction by adjusting cyanide concentration. This, however, must be high enough to ensure pseudo-first-order conditions. A kinetic method using the accelerating effect of histidinol on the oxidation of 1,1,3-tricyano-2-amino-l-propene by H202 in the presence of Cu(I1) ions has been proposed for the determination of histidinol (211). The reaction is fluorometrically monitored (excitation at 350 nm; emission at 430 nm) and histidinol can be determined in the to lo4 M range. Potentiometric monitoring of the periodate reaction with tartaric acid by means of a liquid-membrane periodate-selective electrode permits the determination (initial rate measurement) of tartaric acid in the 0.4-120 p M range (212). The method was used to determine tartaric acid in pharmaceutical preparations and in impure citric acid. Karayannis et al. (213) reported on the reaction rate determination (variable-time procedure) of nitrite by photometrically following the Griess reaction (red azo dye formation from sulfanilic acid and 1-naphthylamine) after stop ed-flow mixing. They report that as little as 1 X lo4 M N&- can be determined by this approach. A fixed-time (5 min) determination of bromate based on its oxidation of Pyrogallol Red has been
KINETIC ASPECTS
OF ANALYTICAL CHEMISTRY
Table 11. Selected Determinations Based on Chemi- and Bioluminescence determined species
comments
ref
flow injection system with a gas diffusion cell; limit of detection about 5 ppb using luminol chemiluminescence chemiluminescence generated by ultrasonic irradiation of alkaline luminol solution in cobalt presence of Co(I1); flow injection determination at fractions of pg levels and at a sampling rate of 120 samples/h; possible explanation of sonic chemiluminescence given chemiluminescence of the 4-(diethylamino)phthalhydrazide-H2O2reaction in alkaline copper medium; limit of detection, 0.05 ng/mL; determination in high-purity gallium luminol chemiluminescence in absence of oxidant in continuous-flow system. iron(II), titanium(II1) Determination at the lo* M level; titanium down to lo* M. Removal of oxygen and used of Rhodamine B as sensitizer improve sensitivity direct determination of Hz02in the to lo4 M range using horseradish peroxidase HzOz,cholesterol mediated luminol chemiluminescence; horseradish peroxidase immobilized on preactivated polyamide membranes; addition of soluble cholesterol oxidase permits cholesterol determination by H20z detection in the cholesterol + O2 reaction; response time is dependent on cholesterol concentration osmium tetroxide, copper(II), hydrogen osmium and copper determined by their inhibition of the luminescence from the peroxide, and hydroquinone luminol-hexacyanoferrate(II1) reaction; hydrogen peroxide by its intensification of the same luminescence in presence of OsO,; hydroquinone is previously oxidized by O2 to Hz02which is then determined; limits of detection in the lo4 to M levels iodide oxidation to iodine by bromine or 1,3-dibromo-5,5-dimethylhydantoin; iodine converted to ICN which is determined by reaction with luminol; detection limit, 5 ng/mL; analysis of river and mineral waters; interference by calcium and magnesium removed before determination chemiluminescence of the eosin-Y reaction with O3in ethylene glycol medium; limit of ozone detection, 0.2 ppb; linear response up to 400 ppb chemiluminescence with rhodamine B; determination in atmospheric water droplets and ozone-treated water; concentration range, 1-10 ng/mL; halide ions, aldehydes, and hydrogen peroxide interfere use of dipyridyl chemiluminescence in conjunction with the bromate-malonic acid-Ce(II1) ruthenium oscillating system; repeated chemical excitation of ruthenium ion during a single M oxidation cycle permits detection at correlation between oscillation of the chemiluminescence and potentiometric monitoring of Ru(bipy)2+ recently described detection of hydrogen peroxide formed by sequential catabolism of purines by the adenosine, inosine, and hypoxanthin/ luminol/peroxidase reaction; automatic procedure (200samples per day) requiring 0.1 xanthine mL of sample and using commercially available luminescence analyzer adenosine 5'-triphosphate nylon tube reactor with immobilized firefly luciferase incorporated to a continuous-flow system; linear calibration curves in the 0.3-100 pmol level; one reactor good for analysis of about 900 samples and retains 50% activity (at 25 "C) for about 15 days chemiluminescence of the reaction of the analyte and triethylamine; limit of detection (in benzoyl peroxide chloroform) 0.7 pg/mL; determination in pharmaceutical preparations corticosteroids and p-nitrophenyl esters postcolumn chemiluminescence detection with lucigenin after HPLC separation hydrogen peroxide produced by oxidation of polyamines with serum amine oxidase diamines and polyamines measured by luminol chemiluminescence; determination in the 10-100 pmol range; applicable to determination of urinary polyamines flow injection procedure based on the decrease of chemiluminescence from the human and bovine serum albumin luminol-hydrogen peroxide reaction; minimum detectable quantities, 10 ng for human serum albumin and 4 ng for bovine serum albumin determination in aqueous-acetone alkaline medium; luminescence from hydrogen peroxide nitrocellulose oxidation of lophine is enhanced by nitrocellulose; limit of detection, 3 X lo4 g/mL enhancement of chemiluminescence due to the 1,lO-phenanthroline-hydrogenperoxide protein reaction in presence of Cu(I1); flow injection determination at about 20 samples/h; sensitivity 40 times better than using luminol-H202 system; minimum quantity detected, 250 pg flow injection system; enzymatic conversion to a glucose (by invertase and mutarotase); sucrose luminol chemiluminescence detection of generated H202;use of especially designed microporous membrane flow cell; concentration range amenable to determination, 5 p to 1 mM; application to analysis of soft drinks, breakfast cereal, and cake mix ClOZ
described by Medina-Escriche et al. (214).A limit of detection of 7 X lo-' M and a limit of quantitation of 2.3 X lo* M are reported. Koukli and Calokerinos (215)used a variable-time procedure for the determination of sulfite, sulfide, ascorbic acid, thiosulfate, arsenic(III), isoniazid, and hydrazine, by monitoring (with an iodide-selective electrode) the iodide produced in the reaction with iodate. The metal chelate formed by reaction of aluminum ion and 2-hydroxy-1-naphthaldehyde p-methoxybenzoylhydrazone,fluorescesces at 475 nm (excitation at 420 nm). This fluorescence was used by Ioannou and Piperaki (216)for an initial-rate determination of aluminum in serum. The proposed method is comparable in sensitivity, but simpler, with the widely accepted atomic absorption determination. The slow complexation reaction of Cu(I1) with 5,5-dimethyl-1,3-cyclohexanedionebis(4phenyl-3-thiosemicarbazone) in 2.5-3.0 M HCl has been used
185 186 187 188 189
190
191
192 193 194 195 196 197 198 199 200 201 202 203
204
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by Rodriguez et al. (217)for a selective determination of copper in the 0.8-8 pg/mL range. Both fixed-time measurement (50 min after starting the reaction) and the method of tangents were used with photometric monitoring of the colored product (430nm) at 60 "C. Abretch-Gary et al. (218) reported on a study of the basic thermodynamics and kinetics of niobium(V) complexation by 4-(2-pyridylazo)resorcinol, PAR, and proposed a kinetic method for niobium determination by a fixed-time procedure. The interference of tantalum(V) is eliminated by masking with tartrate. The deM. The rate termination range is from 5 X lo-' t o 2 X of color formation is monitored at 550 nm and the optimum pH is about 6.00.
DIFFERENTIAL RATE METHODS The number of differential rate procedures recorded in the literature during the past two years has shown an increase. ANALYTICAL CHEMISTRY, VOL. 60, NO. 12, JUNE 15, 1988
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The majority of the reported rocedures are for inorganic (mostly transition-metal ions andjanions of nonmetals) species. A unique application of differential ligand exchange kinetics projecting beyond determination has been reported by Lavigne et al. (219). They studied the ligand exchange between fulvic acid-Ni(II) complexes and PAR and applied the observations collected to the speciation of Ni(I1) bound to fulvic acid. The data treatment was aided by use of an approximate Laplace transform and nonlinear regression. Differences in the rate of ligand substitution of the Zn(II), Mg(II), Cu(II), and Ni(I1) complexes with 3-hydroxy-4-(2hydroxy-5-methylpheny1azo)naphthalene-1-sulfonicacid (camalgite) and EDTA have been used by Mentasti et al. (220) for simultaneous determinations in binary and ternary mixtures at the lo4 M level. Stopped-flow mixing and photometric monitoring a t 500 nm were used, and a logarithmic extrapolation approach was adapted for data treatment. The proposed procedure was applied to the determination of magnesium in samples of river, tap, and mineral waters. Calcium does not interfere because its complex with camalgite reacts with EDTA considerably faster. Cobalt, copper, and nickel in binary and ternary mixtures have been determined at the ccg/mL level by a differential method based on 1,2cyclohexanediaminetetracetate,CDTA, displacement of the metal ions from their complexes with pyridoxal thiosemicarbazone (221). The course of ligand substitution was photometrically followed a t 425 nm. Single point and logarithmic extrapolation procedures were used for data treatment. The same authors took advantage of the different rates of complexation of nickel and copper with pyridoxal thiosemicarbazone for their simultaneous determination in mixtures (222). Three approaches to data treatment (logarithmic extrapolation, single point, and a reaction rate measurement approach) were compared; a wider range of concentration is amenable to determination by using the logarithmic procedure. Submicrogam amounts of copper(I1) and zinc(I1) in serum have been determined by a differential reaction rate procedure based on the rate of metal ion incrporation into N-methyl5,10,15,20-tetrakis(4sulfonaphthophenyl)porphine (223). The acid dissociation reaction of the cadmium(I1) and zinc(I1) complexes with the same ligand is about 10l2times faster for copper (224). Although no simultaneous determination has been reported, this rate differential has been used for the determination of zinc in the presence of excess cadmium by photometric monitoring (421 nm) of absorbance after 30 s and 5 min (fixed-time measurements) (224). The procedure was applied to determine zinc in river and tap water and in cadmium sulfate. A unique chemical situation has been exploited by Abe et al. (225) for the simultaneous determination of iron(I1) and iron(II1) in aqueous solutions. The approach is based on the aerial oxidation of iron(I1) in the presence of sodium 4,5-dihydroxybenzene-l,2-disulfonate(Tiron) and acetate ions (acetate buffer pH 3.5). The iron(II1)-Tiron complex absorbs 558-nm photons and absorbance values at zero time and a t equilibrium, calculated by nonlinear regression of the absorbance vs time curve, give the iron(II1) and total iron in the sample. The iron(I1) is obtained by difference. Determination of rate coefficients is not needed. The formation of double peaks in flow injection signals when relatively large sample volumes are injected was pointed out by Painton and Mottola (226). This observation was exploited by Fernhdez et al. (227) to create two reaction zones permitting differential determinations. Cobalt and nickel in mixtures (complex formation with 2-hydroxybenzaldehyde thiosemicarbazone) were determined by evaluation of the increment in peak height (or peak area). After determining the rate coefficients for the hydrolysis of pyrophosphate and tripolyphosphate ions at 70 "C and 1.0 M HC1, Messrabi et al. (228) used them to demonstrate their use in the simultaneous determination of these species in mixtures. Two different sets of experimental conditions, molybdate being used to mask periodate ion in one of them, have permitted the resolution of iodate and periodate ion mixtures at the pg/mL level (229). These determinations are based on the oxidation of the iron(I1) complex of dipyridylglyoxal dithiosemicarbazone. Kinetic measurements involved evaluation of initial rates. Silicate and phosphate in water samples have been determined by taking advantage of the rate difference in the formation of their molybdoheteropoly acids l94R
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(230). Unsegmented-continmuous-flow sample/reagent(s) processing and fluorometric detection allow determination in 60 samples in 1 h, in the 30 to 600 ng/mL range, and in silicate/phosphate ratios of 1:lO and 1O:l. Individual as well as simultaneous (differential rate) determinations of perphenazine and chlorpromazine using stopped-flow mixing and fluorometric monitoring have been proposed by Gutierrez et al. (231). Dissolved oxygen acts as oxidizing agent and initial rate measurements are used in a kinetic procedure comparable in performance to determinations based on the measurement of maximum fluorescence intensity. Application to the determination of the drugs in pharmaceutical preparations is reported. The differential determination of imidazole and 4-methylimidazole based on the enhancement by these species of the fluorescence resulting from HzOzoxidation of 1,1,3-tricyano-2-amino-l-propene in the presence of Cu(I1) has been proposed (232). Because of the similar behavior of both species and the presence of synergistic effects, the determination makes use of initial rate data and maximum fluorescence intensity (233). From the same group of researchers has come a differential reaction rate method for the determination of histidine and histamine at the M level in their mixtures, in which synergistic efects are taken into consideration (234). The method uses fluorometric monitoring based on the increase in the fluorescence intensity of the 1,1,3-tricyano-2-amino-1-propene-H&Cu(II) system. The difference in the rates of furfural and vanillin reaction with p-aminophenol permitted simultaneous determination of these species in a continuous-flow system (235). Single sample injection and a single detector were employed. Different residence times of two monitored plugs created by splitting just after sample injection provided the discriminating variable. Linares et al. (236)have proposed flow injection systems for the sequential, simultaneous, and differential kinetic determination of pyridoxal and pyridoxal 5phosphate. The determination is based on the aerial oxidation of the analytes in presence of cyanide and monitoring (fluorometrically) the oxidation products.
KINETICS IN SOME SEPARATION PROCESSES Two areas dominate the interest of kinetics in separation processes: single-stage phase separations (e.g. solvent extraction) and multistage separations represented by chromatography. A greater awareness of the kinetic nature and potentials of chromatography is responsible for a larger number of contributions to the literature in the past two years. Single-phase Separation Processes. The kinetics of adsorption processes has been discussed in some detail by Sircar and Myers (237). The use of the rotating diffusion cell technique in the study of kinetics in solvent extraction processes has been considered by Dreisinger and Cooper (238). A rate and mechanistic study of liquid-liquid segmentedcontinuous-flow systems has been presented (239). This study points toward miniaturization as the avenue to achieve high extraction rates and a decrease in sample-zone dispersion. Inaba and Sekine (240)have measured the rate of extraction of Fe(II1) with trifluoroacetone from aqueous perchlorate into carbon tetrachloride. They conclude that chemical equilibria of stepwise complex formation affect the rate of extraction. Formation of the first complex is rate determining. Individual rate coefficients for the extraction of nickel (from aqueous solution into chloroform) by 8-quinolinol, and its high molecular weight analogue known as Kelex 100, have been reported by Aprahamian and Freiser (241). A quantitative description of the role of the interface in the kinetics and mechanism of extraction is presented. The kinetics of copper(I1) extraction from aqueous acetate buffer solutions into kerosene containing Versatic Acid 10 has been reported by Lee et al. (242). The overall process is controlled by the formation step of one of the intermediate complexes between Cu(I1) and Versatic Acid 10. The forward rate of extraction is proportional to the metal ion concentration in the aqueous phase, inversely proportional to the hydrogen ion concentration, and proportional to the Versatic Acid 10 concentration but in a complex form. The kinetics of cobalt and nickel extraction with (2-ethylhexy1)phosphonic acid mono 2ethylhexyl ester has been studied by Dreisenger and Copper (243). The data was treated by applying models based on
KINETIC ASPECTS OF ANALYTICAL CHEMISTRY
interfacial and mass transfer with chemical reaction. Such a model describes well the experimental data collected in a wide range of experimental conditions. Kinetics of the extraction and stripping of copper complexed by 2-hydroxy-5-nonylbenzophenoneoxime using heptane as diluent has been studied by Kondo et al. (244). An interfacial reaction model has been used to interpret the data. The quaternary ammonium salt known as Aliquat 3368 has been found to catalyze the extraction of palladium(I1) with 2-hydroxy-5-nonylbenzophenone oxime into heptane-chloroform solvents from acidic chloride media (245). The Aliquat cation helps transfer PdC142-as an ion pair into the organic phase. Chelate formation in the organic phase subsequently releases the Aliquat cation which entering the aqueous phase is available for further transfer of PdCld2-into the organic phase. As little as 2 X lo4 M thiocyanate added to aqueous chloride solutions of palladium increases the rate of palladium extraction into Kelex 100 by over 600 times (246). Iodide and bromide also produce rate increases but in lesser extent. The rate enhancement correlates with the size of the “trans-effect”, SCN- > I- > Br-, in easing the replacement of a coordinated chloride ion by Kelex 100.
Multistage Separation Processes (Chromatography).
Zelinka (247) has described a method for evaluating the kinetics of dynamic gas extraction. This work is of interest in the determination of organic species by headspace gas . - chromatography. ChromatoeraDhic reactors and on-column rate coefficients have been shyokn to provide useful information in the characterization of solute-stationary phase interactions in reversed-phase systems (248)and for the determination of phase ratios in liquid chromatography (249). The applicability of these reactors for kinetic studies to define optimum chromatographic conditions has also been demonstrated (250). Kinetic parameters in ion-exclusion chromatography have been determined by Goto and Goto (251). The study involved the separation of sodium chloride and alcohols. Axial dispersion and intraparticle diffusion were found to be the factors dominating the separation of alcohols. A method for the determination of the initial content of a reacting substance in the column of a as chromato raph has been outlined by Stolyarov et al. (2527. The metho8 is applicable to any species undergoing first-order reaction in the reactor column and uses a single-cycle operation to determine the rate coefficient and the amount of product formed. The coefficients of mass transfer of some proteinic materiels on small reversed-phase chromatographic columns were determined by a kinetic approach based on “split-peak”behavior (253). Results were not affected by interactions between the proteinaceous material and the stationary phase. The kinetics of slow diffusion and slow adsorption in an a f f d t y chromatographic situation has been discussed by Hage et aL (254). Depending on the method of immobilization either adsorption or diffusion can be the determining step. Theoretical considerations and experimental evaluation of micellar-mediated molecular diffusion have been discussed by Armstrong et al. (255). They used the Taylor-Aris approach to obtain diffusion coefficients and focused their considerations on chromatographic separations.
MISCELLANEOUS KINETIC ASPECTS OF ANALYTICAL INTEREST Consecutive first-order reactions and/or processes are of interest in several situations in contemporary analytical chemistry (256). Moodie (257) has reported on a method to evaluate the constants F and G in the general equation A = P - [Qexp[-(Ft)]] + [R exp[-(Gt)]] in which A is the monitored parameter and P, Q, R, F , and G are constants. The constant F characterizes the faster process and G the slower. Advantages of the approach are, for instance, that if absorptiometric data is monitored, the molar absorptivities are not required to be known and the starting time does not need to be known accurately. A detailed study of the kinetics of series processes taking place in the determination of arsenic(II1) by sodium borohydride reduction to arsine and subsequent atomic absorption measurement has been presented (258). Optimization of absorbance vs time profiles is shown to be aided by control of the kinetic pa-
rameters affecting the value of the rate coefficients for the coupled processes. A mathematical treatment based on diffusion mass transfer and chemical kinetics has been proposed by Schulmeiater (259) to describe the transient response in amperometric multilayer enzyme electrodes. Computer-generated numerical results are presented but correlation with empirical observations is not. A diffusion-kinetic treatment to describe the response in single-enzyme potentiometric and enthalpimetric detectors has been presented by Sorochinskii and Kurganov (260). Arnold et al. (261) have reported time-dependent selectivities for sodium- and hydrogen-selective glass membrane electrodes. A model to account for the dependence on time is discussed. Theoretical aspects of metal electrodeposition on inert solid electrodes have been presented by Sioda (262). The discussion is centered on the kinetics of metal ion deposition from solution and metal ion dissolution and is pertinent to electrodeposition for a preconcentration or preseparation step. Several requirements for observation of room-temperature phosphorescence using micelle stabilization have been discussed by Sanz-Medel et al. (263). Niobium(V) was determined in complexation with 8-hydroxy-7-iodoquinoline-5sulfonic acid, ferron, in micelles of cetyltrimethylammonium bromide. The limit of detection is reported as 4 ppb. A special issue of the journal Analytical Instrumentation has been dedicated to time-resolved fluorescence spectroscopy; of particular interest is a paper by Birch and Imhof (264) on the kinetic interpretation of fluorescence decay. The discussion is illustrated with applications that cover polymers, membranes, scintillators, and solar collectors. Time-resolved fluorescence measurements with an optical-fiber probe about 16 m long were made by Vickers et al. (265). The work was designed to investigate the limitations of remote fluorescence sensing caused by temporal broadening. Fibers as long as 1 km seem usable without much deterioration in accuracy or precision. Bacigalupo et al. (266) proposed a time-resolved immunofluorometric determination of progesterone. The method makes use of europium-labeled protein-A and the europium bound is determined as the 2-naphthoyltrifluoroacetone chelate by time-resolved fluorescence measurement. A comparison of a time-resolved immunofluoromeric determination of corticotropin and an immunoradiometric one, using the same antibodies, has been reported (267). The time-resolved procedure is considered simpler and precise and offers an attractive alternative for nonradiometric determination of corticotropin. The Jaff6 reaction is routinely used for creatinine determination in biological fluids. Many studies have been published pointing to different aspects of the chemistry of its reaction with picrate ions with the aim of improving the determination. Pardue et al. (268) revisited this reaction and have recently reported on the kinetics of the reaction of creatinine and picrate in basic medium. Their studies, aided by nonlinear curve-fitting methods, offer several observations of utility to those using the Jaff6 reaction in clinical chemistry. The pseudo-first-order coefficient for this reaction has been found to change logarithmically with temperature and this behavior has been used to calibrate the thermostating system maintining the temperature around the optical path of a spectrophotometer (269). The calibration is in the 25 to 37 “C temperature range. Continuous-flow sample/reagent(s) processing continues attracting interest and some basic studies have been reported in the past two years. Jager and Pardue (270),for example, presented a kinetic treatment taking into account detectors with finite sensitivities used in conjunction with unsegmented systems containing a mixing chamber. This contribution corrects for previous similar treatments derived by considering detectors with infinite sensitivity. A sto -flow, merging-zones, unsegmented-continuous-flow manifo d and turbidimetric detection of rate have been used by Worsfold et al. (271) for the determination of human serum immunoglobulin G. Turbidimetric monitoring is at 340 nm and the immunoglobulin concentration is interpolated from a second-order fit of calibration data. The reaction rate is measured by stopping a segment of the merged serum and antiserum zones in the flow cell after 14 s of sample injection and measuring the turbidity 30 and 60 s after stopping the zone. As many as 40 samples can be processed per hour. Stults et al. (272) have
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applied a reactor with immobilized glucose oxidase and unsegmented-continuous-flow processing to study the kinetics of D-glucose mutarotation. The study made use of a singlebead-string reactor and the Trinder reaction. This is a good example of the potential of unsegmented continuous-flow processing beyond analytical determinations (273). A theoretical and experimental study of axial dispersion in the presence of secondary flow effects (coiled tubes) in continuous flow has been presented (274). The authors proposed a new way to describe dispersion in such cases, based on the reduced dispersion, which in turn is based on Reynolds and Schmidt numbers. Very few contributions have appeared in the past two years with respect to kinetics in nonflame atomic absorption determinations. An exception is a paper centered on the appearance time for refractory elements (e.g. molybdenum, platinum, titanium, and vanadium). This time is shortened by a factor of 2 in furnace tubes made wholly of pyrolytic graphite as compared to conventional electrographite and pyrolytically coated electrog-raphite tubes (275). Faster heating in the totally pyrolytic tubes also shows improvement in the time of appearance for medium-volatile elements (e. . chromium and manganese); no significant difference was otserved with volatile elements (e.g. cadmium and lead). The improved performance permits reduction of atomization times and resulk in an increase in tube lifetime. Kinetic information (rate coefficients) for the stability of group Vb element hydrides can be found in a paper by Fujita and Takada (276). Arsenic and antimony hydrides are comparatively stable but the hydride of bismuth is both thermally and kinetically unstable. Wood et al. (277) have shown that a kinetic version of the o-phthalaldehyde method for urea determination eliminates errors due to interference by monoclonal proteins. The kinetics of binding and removal of metal ions [Hg(II), Cu(II), Ag(I)] in reaction with proteins (ovalbumin, myoglobin, lysozyme, and insulin) and of reactions of the same proteins with some organometallic compounds [methylmercury(I) and p chloromercuribenzoate] have been studied by using fluorometric monitoring (278). Sites at which multiple binding occurs with different rate coefficients can be kinetically differentiated by both formation and removal processes. 2,4,6Trinitrobenzenesulfonic acid, TNBS, is used as a specific reagent for primary amino groups. The kinetics of its reaction with amino acids has been potentiometrically studied with a TNBS-selective electrode (279). Gorshkova et al. (280)have studied the effect of aldehydes on the reaction between o-phenylenediamine and hydrogen peroxide. Condensation of aldehydes with o-phenylenediamine is said to play a key role in the process leading to the formation of benzimidazole as final product. A reaction rate determination of p - (dimethy1amino)benzaldehyde has been proposed based on these studies. The effect of dimethylformamide and acetic acid on the kinetics of the reaction between gallium and Picramine M has been investigated (281). This reaction is the basis for a method to determine gallium. Approaches to minimize errors inherent in fluctuations of rates caused by experimental parameter uncertainties continue to attract increase interest. Pardue and co-workers, for instance, further demonstrate the usefulness of multipoint data processing in kinetic-base determinations. Skoug and Pardue (282) have applied multipoint measurements and data treatment in the determination of immunoglobulin G based on its reaction with antibodies. Stopped-flow mixing and nephelometric monitoring were used to determine the antigen in the 0-73 mg/dL range. Weiser and Pardue (283) applied the approach to the immunochemical determination of isoenzyme forms of creatine kinase. Centrifugal mixing with photometric monitoring was used this time. An ineresting look at the rate-concentration curve for enzyme-catalyzed reactions has been provided by Goren and Davis (284). They show that although this curve is commonly assumed to be hyperbolic and the linear range limited by the value of the MichaelisMenten constant, KM,the curve is sigmoidal in shape beyond initial rate measurements. As such linear data can be obtained for substrate concentrations greater than KMby proper selection of the enzyme activity of the reagent and the measurement interval. Effects that can introduce between-run variations in rate coefficients are cancelled in a two-rate measurement proposed by Wentzell and Crouch (285). The approach was tested with two chemical systems (a metal exl96R
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change reaction and molybdophosphate formation) under conditions which pH and temperature fluctuations introduce large changes in the values of rate coefficients. The method was subsequently compared with more conventional reaction-rate approaches which rely on first-order kinetics (286). Advantages of the derivative approach to initial rate measurements over inte a1 estimation have been considered by Casado et al. (287). Tfe collection of absorbancetime data is a very common task in reaction rate determinations. In these cases the need to obtain values for rate coefficients under first- or pseudo-first-order conditions is also a common practice. The precision of such estimation depends on the precision of measurement of absorbance as well as time and has been discussed in detail in a paper by Johnson et al. (288). They report that if the standard error of a measurement of time is below about 0.005 the half-life for the chemical reaction, the standard error of the rate coefficient is practically the same by following either reactants or products. For larger values, however, it is better to follow reactant(s) concentration. The paper points out that errors in the measurement of time may be more significant than they have been assumed to be.
INSTRUMENTATION AND COMPUTERS During the past tweyear period, there has been a significant decrease in the number of papers dealing directly with instrumentation, automation, theoretical calculation and modeling, data handling, etc., which deal specifically with kinetic measurement which have applicability to chemical analysis. It appears that researchers in this area feel that the number of “tools” available fo’; kinetic methods of analysis is unlimited and the important direction of research, as observed by the above sections of this review, is the development of practical methods of analysis. This section of the review is divided into the following categories: (i) Detectors, (ii) Instrumentation, (iii) Computer Instrumentation, and (iv) Papers of Potential Analytical Interest and Theory. Again, the readers will find some repetition of citations in this section that were also discussed in the above sections. Some papers contain both new instrumentation developments or design and also present new analytical procedures as well. With respect to papers devoted primarily to the design and development of flow-through detectors, the following are considered to be the most applicable for kinetic methods of analysis. Christopaulos and Diamandis (289) have designed a variety of flow-through detection units for solid-state, liquid, and PVC matrix membrane ion-selective electrodes which minimize streaming potentials. Blanco et al. (290) have described diode-array detectors for FIA for mixtures using the resolution available for multiwavelength analysis. The design and characterization of a diode-array data acquisition system for spectrometric measurement have been given by RyanHotchiss and Ingle (291). Although not specifically designed for flow detection applications, the fluorescence inner filtering double-pass cell configurations have great potential. Street (292)has demonstrated the validity of various assumptions involved in the primary inner filtering diagnosis theory. Girotte et al. have designed bioluminescent flow sensors which have tremendous potential in FIA and other kinetic based methods (293). Suzuki et al. (294) have designed a fluorometric cell detection system using complement-mediated cytolytic reaction and imaging sensor systems which should be applicable to flow analysis. A unique detection system using a carbon black detector-visible spectroscopy of liquid employing photoacoustic spectroscopy (PAS) has been reported by Ates (295)which also should be applicable in flow applications. Fiber-optic probes (or sensors) have fantastic potential for flow detectors and kinetic analysis. One application for the kinetic determination of enzyme activities has been reported (296). The use of a large volume wall-jet detector for computer-assisted rapid-scan cyclic staircase voltammetry in normal-phase HPLC which would also be applicable to FIA, etc., methods has been developed by Gunasingham et al. (297). The advantages of direct reaction monitoring using supercritical fluids as solvents in conjunction with Fourier transform infrared spectroscopy (FT-IR) has been reported by Olesik et al. (298). A capillary system was used in the ”flow-injection analysis” mode. With respect to new instrumental developments, Lazaro et al. (299) have proposed “doubly stopped-flow’’ as a new alternative to simultaneous kinetic multideterminations in
KINETIC ASPECTS OF ANALYTICAL CHEMISTRY
unsegmented flow systems. With respect to stopped-flow instrumentation, Loriguillo et al. have designed a versatile computer automated system which features a mixing module that is compatible with many different spectrophotometers and spectrofluorimeters (300). A very interesting and potentially useful sample insertion technique which injects the sample between two different standard solutions used as the carrier streams have been reported by Alonso et al. (301). They called this an FIA “sandwich technique”. Fernandez et al. (302) have devised a flow-injection system for kinetic determinations based on the use of two serial injection valves. Nemeth et al. (303) have developed a method for the rapid measurement of rate parameters by the pulsed-acceleratedflow method. In the domain of computer developments applicable to kinetic-based analytical methods, Nelson et al. have developed an inexpensive intelligent interface for coupling a PRA fluorescence lifetime instrument to a Microvax I1 computer (304). Pentari and Efstathion (305) have reported the construction and application of a microcomputer-controlled pulsed amperometric detection system for various organic analytes. Lochmuller et al. (306) have discussed the performance and the use of a Zymatic I laboratory robot. They evaluated its potential for nonroutine applications. A discussion of simultaneous optimization of variables in FIA systems by means of the simplex method has been given by Alonso et al. (307). Of potential application in kinetic analysis is a microcomputerized ultrahigh speed transient digitizer and luminescence-lifetime instrument designed by Turley et al. (308). Dohmen and Thussen (309) have designed an automated FIA system with computer-controlled sample changer, injection device, and digital spectrophotometer. Also, Peterson et al. have developed an automated stopped-flow spectrophotometer for the determination of rate parameters which also could be used in analysis (310). Theoretical (and experimental verification) studies by Stults et al. have examined the effect of temperature on dispersion in FIA. Significant predictable effects were found which agree with the random walk model (311). Crowe et al. have examined random walk simulations in FIA with merging stochastic zones (312). Variables examined were reagent plug size and offset, reagent concentration, diffusion coefficient, viscosity, and temperature. Kolav and Pungor (313) have examined numerical solutions of hydrodynamic models based on an axially dispersed plug-flow model by Laplace transforms. They have also examined (314) the “end effects” in FIA which was theoretically studied also using an axially dispersed plug-flow model. In a more miscellaneous instrumental and theoretical paper applicable for kinetic based analysis, Silver (315) has developed an operational method of slope estimation which certainly can be employed with analytical kinetic data. The determination of kinetic parameters from pulse voltammetric data has been discussed by O’Dea et a1. (318). A very interesting examination of acoustic emission from a model chemical process predicts this as a method for monitoring chemical processes. Belchamber et al. (319) have studied acoustic emission as a model chemical process (also a potential monitoring method). Caprioli and Smith (320) have determined the “kinetic parameters” KM and V,, for an enzyme reaction using fast atom bombardment (FAB) mass spectrometry. Chu and Langer (321) have measured reaction rate constants in the liquid chromatographic reactor (mass transport effects). Greinke (322) has used analytical kinetic techniques to study the polymerization petroleum pitch gel chromatography. Gel permeation chromatograph was a surprising or unusual method applied to kinetic stuiy. This paper was selected as one of the two best papers published in the journal Carbon, 1985-1986.
ACKNOWLEDGMENT The authors acknowledge research support from the Spanish Government (D.P.-B.) and the Office of Basic Energy Sciences, U.S.Department of Energy (H.A.M.). This review is a byproduct of such a support. LITERATURE CITED
(1) Mottola. H. A.; Mark, H. B., Jr. Anal. Chem. 1988, 58,264R-279R. (2) Mottola, H. A. Analyst (London) 1987, 112, 717. (3) Dawen, Y., Jlangxi University, personal communlcatlon, 1987.
(4) Robinson, K. A. Chemlcal Analysis; Little, Brown and Co.: Boston, MA, 1987;Chapter 11. (5) Mottola, H. A.; Mark, H. B., Jr. I n Instrumentel Analysls, 2nd.ed.; Christlan, 0. D., O’Rellly, J. E., Eds.; Allyn and Bacon: Boston, MA, 1986; Chapter 18. (6) Chrlstkn, G. D. Analytical Chemlstty, 4th ed.; Wiley: New York, 1986; Chapter 18. (7) Mottola, H. A. Kinetic Aspects of AnalyHeel Chemlsby; Wlley: New York,
1988. ( 8 ) Kamentseva. 0. V.; Zoiotova, G. A.; Doimanova, I. F. Zh. Anal. Khim. 1966,4 1 . 1749-1784;J . Anal. Chem. USSR(Engl. Transi.) 1988,4 1 ,
1203-1217. (9) Yatsimlrskll, K. B.; Tlkhonova, L. P. Talanta 1987, 34, 89-75.
(IO) Ramls Ramos. G.; Garcla Alvarez-Coque, M. C.; Villanueva CamaRBs.
R. M. Analyst (London) 1088, 7 1 7 , 1001-1012. (1 1) Yamane, T. J . Flow InJectlon Anal. 1988,3 , 77-90. (12) Valdrcel, M. Analyst (London) 1987, 112,729-737. (13) Mottola, H. A. Analyst(London) 1987, 172,719-727. (14) Gail, F. F. Analyst (London) 1087, 172, 739-751. (15) Hutte, R. S.;Sievers, R. E.; Birks, J. W. J . Chromatogr. Sci. 24,
499-505. (16) &get, C.; Serpinet, J. Analusis 1988, 14, 55-66. (17) Rao, S. J.; Reddy, G. S.; Kumarl, J. K.; Reddy, Y. K. Analyst (London) 1988, 1 1 1 , 245-246. (18) RomBn-Ceba, M.; Jimlnez-SPnchez, J. C.; Galeano-Diaz, T. Rev. Roum. Chlm. 1988,31,889-895. (19) Llobat-Estellls, M.; Sevillano-Cabeza, A.; Medina-Escriche, J. Analyst (London) 1988, 1 1 1 , 193-195. (20) Medina-Escriche, J.; HernBndez-Llorens, M. L.; Liobat-Estellls, M.; Sevillano-Cabezas, A. Analyst (London) 1987, 172, 309-31 1. (21) Nabl, A.; Worsfoid, P. J. J . Chem. SOC.Pak. 1988, 8 , 487-490. (22) Deguchi, T.; Higashi, A.; Sanemasa, I . Bull, Chem. SOC.Jpn. 1988,
59,295-300. (23) Isshiki, K.; Nakayama, E. Talenta 1987,34, 277-281. (24) Kubaszewski, E. Chem. Anal. (Warsaw) 1985,30, 519-526. (25) Jardlm, W. J.; Rohwedder, J. J. R. Analyst (London) 1088, 1 7 , 849-850. (26) Medlna-Escriche, J.; HernBndez-HernBndez, P.; Lbpez Benet, F. J. Analyst(London) 1985, 110, 1457-1461. (27) Borrull, F.; CerdB, V. Thermochlm. Acta 1987, 112,335-340. (28) Bllenko, D. A.; Mustakova, S. P. J . Anal. Chem. USSR (Engl. Trans/.) 1085,4 0 , 1247-1251. (29) Nakano, S.; Ihara, H.; Tanaka, M.; Kawashlma, T. Mlkrochlm. Acta 1085,I , 455-465. (30) GutiBrrez, M. C.; Gmez-Hens, A.; ValcBrcel, M. Talanta 1988, 33, 567-570. (31) Gutilrrez, M. C.; G6mez-Hens, A.; D. Plrez-Bendlto, M. Fresenlus’ 2. Anal. Chem. 1987,328, 120-124. (32) Themelis, D. G.; Vaslilkiotls, G. S. Analyst (London) 1987, 112, 797-801. (33) Bilenko, 0.A,; Mustakova, S. P. Zh. Anal. Khim. 1988,4 1 , 85-68; J. Anal. Chem. USSR(Engl. Transi.) 1988,4 7 , 50-53. (34)Weisweller, W.; Malloun, E.; Hohl, K. J. Zem-Kalk-Gips. Ed. 1987,4 0 , 51-53. (35) Ficher, P. W. F.; L’abbe, M. R.; Giroux, A. J. Assoc. Off. Anal. Chem. 1 ~ 8 869,687-689. , (36) Aumont, G.; Tressol, J. C. Analyst(London) 1088, 111, 841-843. (37) Aumont, G.; Tressol, J. C. Analyst (London) 1987, 112,875-878. (38) Tanaka, A.; Obata, K.; Deguchl, T. Anal. Sci. 1988,2 , 197-198. (39) Krlshnamoorthy, K. R.; Iyer, R. K. Proc. Indian Acad. Scl. Chem. Scl. 1987.98. 177-183. (40) V i i s , P.; HernBndezCbrdoba,M.; Snchez-Pedretio, C. Talanta , 1987, 3 4 . 351-354. (41)Kalima, V. E.; Otto, M.; Mueller, C. Izv. Vyssh. Uchebn. Zaved. Khlm. Khlm. Tekhonol. 1088,29,50-52. (42) Bllenko, 0. A.; Mushtakova, S. P. Ukr. Khlm. Zh. (Russ. Ed.) 1988, 52, 1184-1186. (43) VIAas, P.; HernBndezGBrdoba. M.: SBnchez-PedreRo. C. Anal. Ouim. 1088,82,333-337. (44) Plrez-Ruiz, T.; Martinez-Lozano, C. Tomis, V. Oulm. Anal. 1088, 5 , 180-190. (45) Hartofylax, V. H.; Efstathlou, C. E.; Hadjiioannou, T. P. Microchem. J . 1086, 33, 18-24, (46) Yerian, T. D.; Hadjiioannou, T. P.; Christian, 0. D. Takrnta 1088, 33, 547-549. (47) Themelis, D. G.; Vasilikiotis, G. S. Analyst (London) 1987, 112, 791-195. (48) Zoton, A. Ch.; Papadopoulos, C. G. Analyst (London) 1987, 112, 787-789. (49)Vliias, P.; HernBndez-Grdoba, M.; SBnchez-PedreRo, C. Aflnidad 1987, 44,225-228. (50) Tabata, M. Analyst (London) 1087, 112, 141-144. (51) Lbpez-Benet, F. J.; HernBndez-HernBndez, F.; Medlna-Escrlche, J.; Marin SBez, R. Analyst (London) 1988, 1 1 7 , 1325-1330. (52)Rao, S.J.; Reddy, G. S.; Reddy, Y. K. Proc. Indian Acad. Sci. (Chem. Scl.) 1985,95, 557-560. (53) Maspoch. S.; Blanco, M.; CerdH, V. Analyst (London) 1088, 1 7 1 , 69-72. (54) Salinas, F.; Berzas-Nevado, J. J.; Valiente, P. Talanta 1087, 34, 321-324. (55) Alexiev, A. A.; Mutaftchlev, K. L. Mikrochim. Acta 1085,11, 115-125. (56) HernHndezCbrdoba, M.; Visas, P.; SHnchez-Pedretio, C. Talanta 1988, 33. 135-139. (57) Fukasawa, T.; Iwatsuki, M.; Kawakubo, S.; Mochlzukl, M. Mikrochlm. Acta 1988v111, 71-80. (58) Wang, 2.; Zheng, Z.Fenxi Huaxue 1988. 7 4 , 467-468. ANALYTICAL CHEMISTRY, VOL. 60, NO. 12, JUNE 15, 1988
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KINETIC ASPECTS OF ANALYTICAL CHEMISTRY (59) Nakano, S.; Ohta, A.; Kawashima, T. M/krochlm. Acta 1085, I I , 273-282. (60) Grases, F.; March, J. 0.; Forteza. R. Mlcrochem. J . 1085, 3 2 , 367-372. (61) Amberson, J. A.; Svehla, G. Anal. Chlm. Acta 1085, 178. 255-261. (62) Kennedy, J. T.; Svehla, G. Fresenlus’ Z. Anal. Chem. 1088, 324, 19-22. (63) Dacka-Seliga, H. Chem. Anal. (Warsaw) 1085, 30. 881-885. (64) Trojanowlcz, M.; Hulanicki, A.; Matuszewiski, W.; Palys, M.; Fukslewicz, A.; Hulanicka-Michaiak, T.; Raszewiski, S.; Szyller, J.; Agustyniak, W. Anal. Chlm. Acta 1088, 188. 185-175. (65) Vershinina, 0. I.; Nadelyaeva, I. L.; Vershinin, V. I. Izv. Vysh. Uchebn. ZavedKhlm. Khlm. Techno/. 1088, 2 9 , 3-37. (66) Bursakov, S. A.; Gvozdev, R. I.; Kii’dlbekov, N. A.; L’vov, N. P. frlkl. Biokhlm. Mlkroblol. 1087. 23, 284-287. (67) Aiekseeva. I. I.; Soiomonov, U. A.; Bobkova, M. V.; Chernyshova, L. M. Zavod. Lab. 1086, 5 2 , 13-14. (68) Khvorostukhina, N. A,; Khomutova, E. G.; Samuienkova, I. N. Zavod. Lab. 1088, 5 2 , 4-6. (69) Khomutova, E. G.; Khvorostukhina, N. A.; Rysev, A. P.; Samulenkova, I. N. Z. Anal. Khlm. 1085, 4 0 , 301-305; J. Anal. Chem. USSR (Engl. Transl.) 1985, 4 0 , 249-253. (70) Slnchez-PedreAo, C.; Garcia-Car&, M. S.; Aibero-Quinto, M. I. Anal. Qulm. 1087, 8 3 , 78-81. (71) Snchez-PedreAo, C.; HernBndez-C6rdoba, M.; ViAas, P. Anal. Quim. 1988, 82, 198-201. (72) Vlhs, P.; Hernandez-Cbrdoba, M.; Sanchez-Pedrelio, C. Analyst (London) 1087, 112, 1019-1022. (73) Gumenyuk, A. P.; Aleshina, V. V.; Mushtakova, S. P. J. Anal. Chem. USSR (Engl. Transl.) 1086, 4 1 , 1002-1006. (74) Bases, F.; Genestar, G.; Forteza, R. Int. J. Envlron. Anal. Chem. 1088, 2 3 , 321-330. (75) Efremenko, A. A.: Kranyuk, I. I.; Rudenko, B. A.; Kudrin, A. N. J. Anal. Chem. USSR (Engl. Transl,) 1085, 40, 1597-1802. (76) Hawkes, W. C. Anal. Chlm. Acta 1088, 183, 197-206. (77) Hwang, J. M.; Wel, T. S.; Chem, J. M. J. Chin. Chem. SOC. 1088, 33, 109-115. (78) Sevillano-Cabezas, A.; Medlna-Escriche, J.; Llobat-EstellBs, M.; MartinPenella, M. Analyst (London) 1088, 111, 1417-1422. (79) Afonso, A. M.; Santana, J. J.; Garcia-Montelongo, F. Talanta 1088, 33, 779-783. (80) Zheng, 2.;Wu, W. Huaxue Shvl 1087, 9 , 56-58. (81) Arlas, J. J.; Hernlndez-Torres, 0. Qulm. Anal. 1087, 6 , 110-118. (82) Grases, F.; Far, G. Radlochlm. Acta 1088, 3 9 , 81-84. (83) Papadopoulos, C. 0.; Vaslllklotls G. S. Mlkrochlm. Acta 1085, 111, 31-47. (84) Hernlndez-Cbdoba, M.; ViAas, P.; Slnchez-Pedretio, C. Analyst (Lon don) 1085, 110, 1343-1345. (85) Nakano, S.; Yamada, C.; Sakai, M.; Kawashima, T. Anal. Sci. 1088, 2 , 61-65. (86) Amberson, J. 9.; Svehla, G. Anal. Chlm. Acta 1086, 185, 201-208. (87) C l . N. P.; Garcia-Vior, L. 0. Acta Bioqdm. Clln. Laflnoam. 1088, 2 0 , 163- 175. (88) Forteza, A.; Cerdl, V. Anal. Chem. 1088, 5 8 , 453-455. (89) Fukasawa, T.: Kawakubo, S.; Unno, A. Anal. Chim. Acta 1088, 183, 269-274. (90) Hwang, J. M.; Tsung, J. C.; Chem, Y. M. J . Chlm. Chem. SOC. 1085, 32. 405-410. (91) AndrBs-Ordax, F. J.; Arrizabalaga, A. An. Qulm. 1085, 81, 431-433. (92) L6pezCuet0, G.; Cueto-Refin, A. ffrst Int. Symp. on Kinetics in Ana!vtical Chemistry Poster P, I, 3. (93) L&ez-Cueto, G.; Cueto-Rejh A. F. Anal. Chem. 1087, 59, 845-648. (94) Labuda, Y.; Yatslmlrskll, K. B.;Kol’chinskli, A. G.; Kwgova, E. Zh. Anal. Khlm. 1088, 4 1 , 85-87; J. Anal. Chem. USSR(Engl. Transl.) 1088, 4 1 , 67-69. (95) Peinado, J.; Toriblo, F.; Pbrez-Bendito, D. Anal. Chem. 1088, 5 8 , 1725- 1729. (96) Peinado, J.; Toriblo, F.; PBrez-Bendlto. D. Taianta 1086, 33, 914-916. (97) Grases. F.: March. J. G.; Forteza, R . J . Radioanal. Nucl. Cbem. 1088, 102, 121-129. (98) Peinado, J.; Toribio, F.; PBrez-Bendito, D. Anal. Chim. Acta 1088, 184 235-242. (99) Cobos, P.; Silva, M.; PBrez-Bendito, D. Analyst (London) 1087, 112, 1441-1443. (100) Sakuragawa, A.; Tamura, K.; Utsuml, S. Bunsekl Kagaku 1088, 3 5 , 95-100. (101) Pantaler, R. P.; Puiyaeva, I. V. Zh. Anal. Khim. 1085, 4 0 , 18541858; J . Anal. Chem. USSR (Engl. Transl.) 1885, 4 0 , 1469-1473. (102)
[email protected].; VillanuevaCamafias. R. M.; Gonzilvez-RodrigoezJ. C.; Carcla AlvarezCoque, M. C. Thermochim. Acta 1087, 112, 171-177. (103) Kurzawa, J. Qulm. Anal. 1085. 4 , 117-128. (104) Kurzawa, J.; Kurzawa, 2. Chem. Anal. (Warsaw) 1088, 31, 45-52. (105) Ciesleiskl, W. Chem. Anal. (Warsaw) 1088, 3 1 , 99-103. (108) Kamentseva, 0. V.; Smirnova, E. B.; Zolotova, G. A.; Dolomanova, I. F. J. Anal. Chem. USSR (Engl. Transl.) 1988, 4 1 , 940-943. (107) Rao, P. P. K.; Sastri, M. N. Indian J. Chem., Sect. A 1985, 2 4 , 539-540. (108) EvmlrMes, N. P.; Karayannis, M. I. Analyst (London) 1087. 112, 831-835. (109) Whiteside, J. R. C.; Worsfold, P. J.; Lynes, A. Anal. Chlm. Acta 1087, 192. 77-83. (110) Aiekseeva, I. L.; Chernysheva, L. M.; Bobkova, M. V.; Solomonov, I. A. Zh. Anal. Khlm. 1087, 42, 362-384; J. Anal. Chem. USSR (Engl. Trans/.) 1087, 4 2 , 296-297. (111) Ghe, A. M.; Stefanelii, C.; Chiavara, G.; Tsiutiki, P. Talanta 1085, 3 2 , 1005-1007
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ANALYTICAL CHEMISTRY, VOL. 60, NO. 12, JUNE 15, 1988
(112) Wimmer, M. C.; Artiss, J. D.; Zak, B. Cllm. Chem. (Winston-Salem N.C.)1088, 32.629-832. (113) Peltl&, J.; Toriblo, F.; P&ez-Bendho, D. Analyst (London)1087, 112, 775-778. (114) Mnovanovic, G. A.; Sekheta, M. A. Mwochem. J . 1088, 32, 342-346. (115) Garcia Alvarez-Coque, M. C.; Vlllanueva-Camaks, R. M.; Ramis-Ramos, G.; Medlna-Hernlndez, M. J.; Mongay-Fernlndez, C. Thermochim . Acta 1088, 103, 325-332. (116) Borruli, F.;Cerd6, V. Thermochlm.Acta 1087. 113, 73-77. (117) Masiowska, J.; Leszcynska, J. Taianta 1085. 3 2 , 883-886. (118) Llzaro. F.; Luque de Castro, M. D.; Vaidrcel, M. Fresenlus’ Z . Anal. Chem. 1085, 321, 467-470. (119) Igov, R. P.; Pecev, T. 0.; Miletic, G. Z. J. Serb. Chem. SOC. 1088, 5 1 , 277-282. (120) Abramovic, B. F.; Gall, F. G.; Abramovic, B. K. J. Serb. Chem. SOC. 1088. 5 1 , 265-276. (121) Raya-Saro, T.; PBrez-Bendito, D. Anal. Chim. Acta 1088, 182, 163-1 75. (122) Raya-Saro, T.; PCez-Bendko, D. Qulm. Anal. 1985, 4 , 259-271. (123) Srlramam, K.; Sarma, B. S. R.; Kaiidas, K. Indlan Drugs 1085, 2 2 , 544-547. (124) Sriramam, K.; Sarma, B. S. R.; Ravindranath, P. Analusis 1088, 14, 99-103. (125) Kouparis, M. A.; Anagnostopouiou. P.; Maimstadt, H. V. Taianta 1085, 3 2 , 411-417. (126) Moreno, A.; Silva, M.; PBrez-Eendito, D.; VaicBrcei, M. Qulm. Anal. 1085, 4, 39-50. (127) Gall, F. G.; Abramovic, B. F.; Cservenak, R. I. Microchem. J. 1088, 34, 295-304. (128) Gall, F. F.; Topaiov, A. S.; Vitez, 2s. J. Mlcrochem. J. 1088, 33, 71-77. (129) Duan. S.; Li, S.; Luo, M.; Zhan, P. Yaoxue Tongbao 1988, 27, 5 18-5 19. (130) Kashanipour, M.; Evans, S.; DaJer de Torrijos, L. A,; Greenhow, E. Anal. Proceed. 1088, 23, 436-437. (131) Banerjee, R. Coord. Chem. Rev. 1085, 68, 145-167. (132) Haight, G. P.; Jones, L. L. J . Chem. Educ. 1087, 84, 271-273. (133) Chimatadar, S. A.; Nandlbewoor, S. T.; Sambrani, M. I.; Raju, J. R. J . Chem. SOC.Datfon Trans. 1087, 3 , 573-577. (134) Coch-Frugoni, J. A.: Zepka, M.; Rocha-Figueira, A.; Sabina-Campos, A. J. Chem. Educ. 1088. 63, 549. (135) Rizkalla, E. N.; Lajunen, L. H. J.; Choppin, G. R. Inorg. Cbim. Acta 1088, 119, 93-98. (136) Rlzkalla, E. N.; Anis, S. S.; Khaill, L. H. folyhe&on 1087, 6, 403-409. (137) Bobadllla, H.; Declnti, A.; GII, L. Polyhedron 1988, 5 , 1429-1436. (138) Araki, K.; Shiralshi, S. Bull. Chem. SOC. Jpn. 1088, 59, 229-234. (139) Abro, P. W.; Corbett, J. T.; Schroeder, J. L. J. Inorg. Blochem. 1088, 2 7 , 191-203. (140) Dlilard, C. J.; Tappei. A. L. J. Inorg. Blochem. 1088, 2 8 , 13-20. (141) Pelnado, J.; Toribio, F.; PBrez-Bendito, D. Analyst(London)1087, 112, 771-774. (142) Papadopouios, C. G. Mlcrochem. J. 1086, 33, 232-235. (143) SevillanoCabeza, A.; Llobat-EsteiYs, M.; Medina-Escriche, J. Analyst (London) 1085, 710, 1333-1337. (144) Benedini. F.; Nail, M.; Rindone, B.; Toliari, S.; Cenini, S.; Lamonica, G.; Porta, F. J . Molsc. Catel. 1088, 34, 155-161. (145) Tsuruya. S.; Yanai, S.; Masai, M. Inorg. Chem. 1088, 2 5 , 141-146. (146) Yu, J.; Tung, H.; Yeh, A. J. Chin. Chem. SOC. 1085, 32, 439-443. (147) Goyal, S. C.; Saxena, L. K. J. Indian Chem. SOC. 1085, 6 2 , 554-556. (148) b y a i , S . C.; Saxena, L. K. J. Indian Chem. SOC. 1085, 62, 443-446. (149) Grases, F.; Amat, E.; March, J. G. Bull. SOC. Chim. F r . 1985, 4 , 594-596. (150) Gases, F.; Amat, E.; Palou, J . Molec. Catal. 1087, 40, 305-310. (151) Klmura, M.; Ishibashi, M. Inorg. Chlm. Acta 1087, 129, 69-74. (152) Hay, R. W.; Basak, A. K.; Pujari. M. P. Transition Met. Chem. 1088, 1 1 , 27-30. (153) Katz, B. M.; Stenberg. V. 1. fdyhedron 1085, 4 , 2031-2034. (154) Suh, J.; Kwon, 8. N.; Lee. W. Y.; Chang, S. H. Inorg. Chem. 1087, 2 6 , 805-808. (155) Cupta. B.; Gupta, A. K.; Gupta, K. S.; Qupta, Y. K. Indlan J . Chem. 1085, 24A, 927-931. 156) Gupta. A. K.; Gupta, K. S.; Gupta, Y. K. Indian J. Chem. 1086, 25A,
___ ___
853-659
157) Khomutova, E. G.; Khvorostukhina, N. A. J. Anal. Chem. USSR (Engl. Transl.) 1085. 40, 636-639. 158) Mlshra, P.; Khandual, N. C. Indian J . Chem. 1088, 25A. 902-904. 159) Khomutova, E. G.; Khovorostukhina, N. A. J . Anal. Chem. USSR (Engl. Transi.) 1088, 4 1 , 1137-1 142. 160) Awasthi, A. K.; Upadhyay, S. K. Transltlon Met. Chem. 1085, 10, 379-382. 161) Kumar, P.; Gupta, K. C.; Vehari, K. React. Kinet. Catal. Left. 1085, 2 9 , 297-305. 162) Kistayya, T.; Reddy, M. S.; Kandlikar, S. Indian J. Chem. 1086, 2 5 A , 905-907. (163) Taqukhan. M. M.; Shukla, R. S. J . Mol. Catal. 1088, 34, 19-30. (164) Ishikawa, M.; Okamoto, K.; Hindaka. J. Polyhedron 1087, 6, 651-654. (185) Manibala. Singh, H. S.; Krishna, 8.; Tandon, P. K. J. Indian Cbem. SOC. 1085, 62, 434-437. (166) Gases, F.; Genestar, C.; March, J. G.; March, P. J. Radioanal. Nucl. Chem. 1088. 9 9 , 391-396. (167) Amat, E.; March, J. G.; Grases, F. J. Mol. Caul. 1088, 35, 1-7. (168) YanO, Y.; Kimura, M.; Shimaoka, K.; Iwasaki, H. J. Chem. SOC., Chem. Commun. 1088, 2 , 160-161.
KINETIC ASPECTS OF ANALYTICAL CHEMISTRY (169) Gowda, 8. T.; Sherlgara, B. S.; Mahadevappa, D. S.; Rangappa, K. S. I d I a n J . Chem. 1985, 24A, 932-935. (170) Murray, R. W.; Ewlng, A. a.; Dwst, R. A. Anal. Chem. 1987, 59. 379A-390A. (171) Bourdlllon, C.; Laval, J. C.; Thomas, D. J . Electrochem. Soc. 1986, 733,706-711. (172) Heuser, J. R.; Glrard, J. E. Anal. Chem 1985, 5 7 , 2847-2850. (173) Santos, L. M.; Baldwln, R. P. Anal. Chem. 1988, 5 8 , 848-852. (174) Petersson, M. Anal. Chlm. Acta 1988. 787, 333-338. (175) Rusling, J. F.; Connors, T. F.; Owlla. A. Anal. Chem. 1987, 5 9 , 2123-2127. (176) Kakizaki, T.; Hasebe, K.; Yoshlda, H. Nlppon Kagaku Kaishi 1987. 1009-101 5. (177) Chlkryzova, E. 0.; Mashlnskaya, S. Ya; Vataman, I. I. Zh. Anal. Khim. 1985, 40,2199-2203; J . Anal. Chem. USSR(Engl. Transl.) 1985. 40, 1737-1740. (178) Hue, D. N. Zh. Anal. Khim. 1987, 42, 511-513; J . Anal. Chem. USSR (Engl. Trans/.) 1987, 42, 408-410. (179) Kaklzakl, T.; Hasebe, K.; Yoshlda, H. Anawst (London) 1987, 772, 1593- 1596. (180) Hasebe, K.; Kaklzakl, T.; Yoshlda, H. Fresenlus' Z. Anal. Chem. 1985, 322, 486-490. (181) Zarebski, J. Chem. Anal. (Warsaw) 1985, 30, 699-716. (182) Hasebe, K.; Yamamoto, Y.; Ohzekl, K.; Kambara, J. Fresenlus' 2. Anal. Chem. 1988, 323, 464-468. (183) Sanchez Mlslego, A.; Guiberteau Cabanillas. A.; Qarcia-Monco Carra, R.; Car0 Gomez, C.; Garcia Garcia, P. Bull. SOC.Chlm.
[email protected], 94, 555-563. (184) Banlcka, F. G. Talanta 1985, 32, 1145-1150. (185) Hollowell. D. A.; Gord, J. R.; Gordon, G.; Pacey, G. E. Anal. Chem. 1986, 5 8 , 1524-1527. (186) Komatsu, T.; Ohira, M.; Yamada, M.; Suzukl, S. Bull. Chem. SOC. Jpn. 1988, 5 9 , 1849-1855. Zaporozhets, 0. A.; Stepanyuk, S. F. Zh. Anal. (187) Dubovenko, L. I.; Khim. 1985, 40, 1016-1018; J . Anal. Chem. USSR(Engl. Transl.) 1985, 40, 804-806. (188) Alwarthan, A. A.; Townshend, A. Anal. Chlm. Acta 1987, 796, 135- 140. (189) Blum, L. J.; Plaza, J. M.; Coulet, P. R. Anal. Lett. 1987, 20, 317-326. (190) Kallnlchenko, I. E.; Tkachuk, T. M.; Plllpenko, A. T. Zh. Anal. Khim. 1985, 40, 1581-1585; J . Anal. Chem. USSR (Engl. Transl.) 1985, 40, 1237-1241. (191) Plllpenko, A. T.; Zui, 0. V.; Terletskaya, A. V. Zh. Anal. Khlm. W88, 4 7 , 2241-2244; J . Anal. Chem. USSR (Engl. Transl.) 1986. 47, 1604-1607. (192) Ray, J. D.; Stedman, D. H.; Wendel, G. J. Anal. Chem. 1986, 5 8 , 598-600. (193) Takeuchi, K.; Mutoh, H.; Ibusuki, T. Bunseki Kagaku 1987. 36, 311-315. (194) Karavaev, A. D.; Kazakov, V. P.; Tolstlkov, 0. A.; Yakshln, V. V.; Khokhlova, N. L. Zh. Anal. Khim. 1988. 47, 42-45; J . Anal. Chem. USSR (Engl. Transl.) 1988, 47, 30-33. (195) Welgt. H. R.; Junghahnei, 0. 2. Chem. 1985, 2 5 , 382-383. (196) Kather, H.; Wleland, E.; Waas, W. Anal. Blochem. 1987, 763,45-51. (197) Carrea, 0.; Bovara, R.; Mazzola, G.; Girottl, S.; Roda, A,; Ghlnl, S. Anal. Chem. 1@88,5 8 , 331-333. (198) Bowyer, J. R.; Spurlln, S. R. Anal. Chim. Acta 1987, 792, 289-292. (199) Maeda, M.; Tsuji, A. J . Chromatogr. 1986, 352, 213-220. (200) Bachrach, U.; Plesser, Y. M. Anal. B k h e m . 1988, 752, 423-431. (201) Hara, T.; Toriyama, M.; Kitamura, K.; Imakl, M. Bull. Chem. SOC.Jpn. 1985, 5 8 , 2135-2136. (202) Arkhlpov, D. B.; Vorontsov, A. M.; Kanev, A. S. Zh. Anal. Khlm. 1965, 40, 911-914; J . Anal. Chem. USSR (Engl. Transl.) 1985, 40. 728-731. (203) Hara, T.; Ebuchl, T.; Aral, A,; Irnaki, M. Bull. Chem. SOC.Jpn. 1988, 5 9 . 1633-1838. (204) Koerner, C. A.; Nleman, T. A. Anal. Chem. 1986, 5 8 , 116-119. (205) Rlehi, T. E.; Malehorn, C. L.; Hinze, W. L. Ana@t(London) 1986, 7 7 7 , 931-939. (206) Malehorn, C. L.; Rlehl. T. E.; Hlnze, W. L. Ana/yst(London)1988. 7 7 7 , 941-947. (207) Wllhelm. J.; Vlllm, V. Anal. Blochem. 1986, 758, 201-210. (208) Henley, R.; Worwwod, M. Anal. Biochem. 1987, 760, 68-370. (209) Meshkova, S. B.; Korovln, Yu. V.; Poluektov, N. S.; Demeshko. D. V. Zh. Anal. Khlm. 1987, 42, 466-489; J . Anal. Chem. USSR (Engl. Transl.) 1987, 42, 385-388. (210) Cummlngs, H. R.; Pardue, H. L. Clln. Chem. (Wlnston-Salem, N . C . ) 1987. 33, 493-497. (211) Gutlerrez, M. C.; Gomez-Hens, A.; Valcarcel, M. Mlcrodwm. J . 1987, 3 5 , 379-364. (212) Hartofylax, V. H.; Efstathiou, C. E.; Hadjlioannou, T. P. Mlcrochem. J . 1986, 3 3 , 9-17. (213) Karayannls, M. I.; Plperakl, E. A.; Maniadaki, M. M. Anal. Lett. 1988, 79, 13-23. (214) Medlna-Escrlche, J.; SevlHano-Cabeza. A.; Martin-Penella, M.; LlobatEsteiles, M. Analyst (London) 1985, 770, 1467-1471. (215) Koukll, I. I.;Calokerinos, A. C. Anal. Chlm. Acta 1967, 792, 333-336. (216) Ioannou, P. C.; Plperakl, E. A Clin. Chem. (Wlnston-Salem) 1986, 32, 1481-1483. (217) Rodriguez. J.; Garcia de Torres, A.; Cano-Pavon, J. M. Mikrochlm. Acta 1985, I , 69-75. (218) AlbretcbGary, A. M.; Nemra, G.; Nguyen, T.; Woiff. C. M Analusis 1985. 13. 394-400. (219) Lavigne, J. A.; Langford, C. H.; Mak, M. K. S. Anal. Chem. 1987. 5 9 , 26 16-2620.
(220) Mentastl, E.; Dlask, V.; Coe. J. S. Analyst (London) 1985, 770, 145 1- 1455. (221) Ballesteros, L.; Perez-Bendlto, D. Anal. Chlm. Acta 1986, 782, 213-218. (222) Ballesteros, L.; Perez-Bendlto, D. Mkmchlm. Acta 1986, I , 123-134. (223) Funahashl, S.; Ito, Y.; Kaklto, H.; Inamo, M.; Hamada, Y.; Tanaka, M. Mlkrochlm. Acta 1988, I 33-47. (224) Tabata, M.; Oshlta, K.; Tanaka, M. Mlkrochim. Acta 1985, I , 397-404. (225) Abe. S.; Salto, T.; Suda, M Anal. Chim. Acta 1988, 787, 203-209. (226) Psinton, C. C.; Mottola, H. A. Anal. Chim. Acta 1984, 758, 67-84. (227) Fernandez, A.; Luque de Castro, M. D.; Valcarcel, M. Anal. Chim. Acta 1987. 793. 107-118. (228) Mssrabl. M.t Lagrange, P.; Leibenguth, J. L.; Schwing. J. P. Analusis 1987. 75. 132-135. (229) Garrido, A.; Silva, M.; Perez-Bendito, D. Anal. Chim. Acta 1988, 784, 227-234. (230) Linares, P.; Luque de Castro, M. D.; Valcarcel, M. Taianta 1986, 33, 869-893. (2311 Gutlerrez, M. C.; Gomez-Hens, A.; Perez-Bendlto, D. Anal. Left. 1987, 20, 1847-1865. (232) Gutlerrez, M. C.; Gomez-Hens, M.; Valcarcel, M. Microchem. J . 1988, 34, 332-339. (233) Rlos, A.; Silva, M.; Valcarcel, M. Fresenius' 2. Anal. Chem. 1985, 320, 762-768. (234) Gutierrez, M. C.; Gomez-Hens, A.; Valcarcel, M. Anal. Chim. Acta 1988, 785, 83-89. (235) Linares, P.; Luque de Castro, M. D.; Valcarcel, M. Microchem. J . 1987, 35. 120-124. (236) Linares, P.; Luque de Castro, M. D.; Valcarcel, M. Anal. Chem. 1985, 5 7 , 2101-2106. (237) Slrcar, S.; Myers, A. L. Sep. Sci. Technol. 1988, 27, 535-562. (238) Drelsinger, D. B.; Cooper, W. C. Solvent Extraction and Ion Exchange 1988, 4 , 135-147. (239) Nord, L.; Backstrom, K.; Danielsson, L. G.; Ingman, F.; Karlberg, B. Anal. Chim. Acta 1987. 794, 221-233. (240) Inaba, K.; Seklne. T. Anal. Sci. 1987, 3 , 117-120. (241) Aprahamian. E. A.. Jr.; Freiser, H. Sep. Sci. Technol. 1967, 22, 233-242. ~ . . (242) Lee, H.-Y.; Ihm. S.-K.; Lee, D.-H. Solvent Extraction and Ion Exchange 1987, 5 , 55-71. (243) Dreklnger, D. B.; Cooper, W. C. Solvent Extraction and Ion Exchange 1986. 4 . 317-344. (244) Kondo, K.; Funatsu, K.; Nakashio, F. Solvent Extraction and Ion Exchange 1987. 5 . 739-755. (245) Rong, Q.; Freiser, H. Solvent Extraction and Ion Exchange 1987. 5 , 923-937. (246) ACBazi, S. J.; Freiser, H. Solvent Extraction and Ion Exchange 1988, 4 , 1121-1137. (247) Zellnka. L. Fresenius' t .Anal. Chem. 1987, 327, 769-773. (248) Chu, A. H. T.; Langer, S. H. Anal. Chem. 1985, 5 7 , 2197-2204. (249) Chu. A. H. T.; Langer, S. H. J . Chromatogr. 1987. 389, 11-19. (250) Chu, A. H. T.; Langer, S. H. Anal. Chem. 1988, 5 8 , 1617-1625. (251) Goto, M.; Goto, S. Sep. Sci. Technol. 1987, 22, 1503-1514. (252) Stolyarov, B. V.; Kokovlna, L. A,; Kartsova, L. A. Zh. Anal. Khim. 1985, 40, 535-538; J . Anal. Chem. USSR (Engl. Transl.) 1985, 40, 449-452. (253) Larew, L. A.; Walters, R. R. Anal. Biochem. 1987, 764, 537-546. (254) Hage, D. S.; Walters, R. R.; Hethcote, H. W. Anal. Chem. 1988, 5 8 , 274-279. (255) Armstrong, D. W.; Ward, T. J.; Berthod, A. Anal. Chem. 1988, 58, 579-582. (256) Mottola, H. A. J . Chem. Educ. 1981, 5 8 , 399-403. (257) Moodle, R. B. J . Chem. Res. (S) 1988, 744-145. (258) Van Wagenen. S.; Carter, b. E.; Ragheb. A. G.; Fernando, Q. Anal. Chem. 1987, 5 9 , 891-896. (259) Schulmelster, T. Anal. Chim. Acta 1987, 798. 223-229. (260) Sorochlnskil, V. V.; Kwganov. B. I. Zh. Anal. Khlm. 1986, 47, 20552063; J . Anal. Chem. USSR(Engl. Transl.) 1988, 47, 1453-1461. (261) Arnold, M. A.; Zisman, S. A.; Hlse, S. M. Anal. Chim. Acta 1988, 787, 17-29. (262) Sioda, R. E. Talenta 1985. 32, 1083-1087. (263) Sanz-Medel, A.; Martlnez Garcia, P. L.; Diaz Garcia, M. E. Anal. Chem. 1987, 5 9 , 774-778. (264) Birch, D. J. S.; Imhof, R. E. Anal. Instrum. 1985, 74, 293-329. (265) Vickers, 0. H.; Miller, R. M; Hleftje, G. M. Anal. Chim. Acta 1987, 792, 145-153. (266) Bacigalupo. M. A.; Ferrara. L.; Meroni. G.; Ius, A. Fresenius' 2.Anal. Chem. 1987, 328, 263-264. (267) Dobson, S.; Whlte, A,; Hoadley, M.; Lovgren, T.; Ratcilffe, J. Clin. Chem. (Winston-Saiem, N.C.) 1987, 33, 1747-1751. (268) Pardue, H. L.; Bacon, 8. L.; Nevlus, M. G.; Skoug, J. W. Clin. Chem. (Winston-Salem, N . C . ) 1987, 33, 278-285. (269) Armitage, E. K.; Miller, W. 0. Clin. Chem. (Wlnston-Salem, N . C . ) 1987, 3 3 , 1891-1895. (270) Jager, P.; Pardue, H. L. Anal. Chlm. Acta 1986, 787, 343-346. (271) Worsfold, P. J.; Hughes, A.; Mowthorpe, D. J. Analyst(London) 1985, 110. . . ., 1303-1305. . ... . ... . (272) Stub, C. L. M.; Wade, A. P.; Crouch, S. R. Anal. Chem. 1987, 59, 2245-2247. (273) Mottola, H. A. Anal. Chim. Acta 1988, 780, 26-30. (274) Leclerc, D. F.: Bioxham. P. A.: Clifford Toren. E., Jr. Anal. Chim. Acta . 1886, 784, 173-185. (275) Brown, A. A,; Lee, M. Fresenius' 2. Anal. Chem. 1988, 323, 697-70 2. ~
~
ANALYTICAL CHEMISTRY, VOL. 60, NO. 12, JUNE 15, 1988
199R
Anal. Chem. 1988. 60, 200R-211R (278) Fullla. K.: Takada. T. Talanta 1988. 33. 203-207. (277) Wwd. P. L.: Hill. 0.: HIII. P. 0. Clln. chem. (Winston-selem. N.C.) 1987, 33. 723-724. (278) pese*. J. J.: ROISBT. G. L.; Dowe. R. J.: Schnelder. J. Anal. Chlm. Acta 1988. 188. 101-109. (279) Sarantmb. E. G.: Diamandis. E. P.: Karyannis. M. I.Anal. Blamem. 1988. 155. 129-134. (280)Gorrhkova. T. A.; Ea. A. Yu.: Vobdina, M. A,: Nashin. A. N. Z h . Anal. Khh. 1988. 41, 1253-1255; J . Anal. Chem. USSR(Engl. Trand.) 1988. 41, 950-952. n . 1.: Sawin. S. B. Z h . Anal. (281) MBtYeels. I.A,; Pebova. T. V.: P ~ g ~ n l V. Khh. 1988, 41. 1578-1579; J . Anal. Chem. USSR(Engl. Transl.) 1988. 41. 1073-1078. (282) Skoug. J. W.: Pardue. H. L. Anal. Chem. 1988. 58. 2306-2312. (283) Weiser, W. E.; Pardue. H. L. Anal. Chem. 1988. 58. 2523-2527. (284) Garen. M. P.: DBYIS.J. E. Clln. Chem. (Winston-Salem. N.C.) 1988. 32,2021-2025. (285) Wenlzell. P. D.: Crouch. S. R. Anal. Chem. 1988. 58. 2851-2855. (286) Wentrell. P. D.; Crouch. S. R. Anal. Chem. 1988. 58. 2855-2858. (287) Casado. J.: Lopez-Qulntana. M. A,; Lwenzc-Barral. F. M. J. Chem. Educ. 1988. 63.450-452. (288) Johnson. E. D.; Weber. J. P.: Wiles. L. Anal. Chlm. Acta 1985. 178, 9RR-975 . .. . . (289) Christopouios. T. K.: Dlemandls. E. P. Anatyst ( L m ) 1987. 122, 1293-1 298. (290) Bbnco. M.: %ne. J.: Itmriaga, H.: Masipoch. S.;Riba. J. Talanta 1987. ld
0*7-001
-_.-I.~""-.
(291) Ryan-Hotchiss. M.; Ingle. J. D.. Jr. Tala"& 1987, 34. 61-827. (292) Street, K. N.. Jr. Anafysr(Lonbon) 1987. 112. 187-189. (293) Gironi. S : R d a . A,: PhzzI. S.:Canea. G.: PIacBminl. A. C.: Angellahi. M. A.; Bavara. R.: Wllni. S. Anal. Len. 1987. 2 0 , 1315-1330. (294) SUzukl. M.; Tamiya, E.: Karube. I.; KatBska. T.: Tokunaga. T. Anal. Len 1987 20 337-348 (295) ~ t e s I. . s. A " ~ I .Len. 1988, 19, 1893-wo6. (296) Wolfbeis. W. S.Anal. Chem. 1988. 58. 2874-2878. (297) Gunaslngham. H.: Tay. 8. T.: Ang. K. P. Anal. Chem. 1988. 58. ~~~~
22 5 8-225 8.
(298) Olesik. S. V.: French, S. B.: Novotny. M. Anal. Chem. 1988. 58, 2256-2258. (299) Lazano. F.: Luqua de Casho. M. D.; Vakarcel. M. Anal. Chem. 1987. 59. 950-954. (300) Loriquillo. A.: Silva. M.: Perez-Bendllo. D. Anal. Chlm. Acta 1987.
._",I 0 - A "
900
L " ~ 1 1 .
(301) Alonso. J.: Bartreii. J.: Dei Valle, M.: EScaIada. M.: Barber, R. Anal. CMm. A d a 1987. 199. 191-196. (302) Fernandel, A.: Luqua de Casho. M.D.: Valc~rceI.M. Ana@! (London) 1987. 112. 803-807. (303) Nemeth. M. T.: Fogelman, K. D.; Ridley. T. Y.: Margerum, D. W. Anal. Chem. 1987. 59. 283-291~ (30% ~ N ~ I S OG.; ~ . Patonoy, G.: Warner. I. AMI. m t . 1988. 15, 215-225. (305) Pentari, J. C.: Etslamlan. C. E. Anal. Inst. 1988. 15. 329.345, (306) Lochmliller. C. H.: Lloyd. T. L.; Lung. K. R.: Kaizurarh. M. Anal. Len. 1987. 2 0 . 1237-1248. (307) Alonso. J.: Bartroll, J.: Coello, J.: del Vaiie. M. And. Len. 1988, 20. ~~
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(308)TuIey. T. J.: Demas. N. J.; Demas. D. J. Anal. Chlm. Acta 1987. 197. 40.
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