Volumetric and Gravimetric Analytical Methodls for Inorganic Compounds W . H . McCurdy, Jr., University o f Delaware, Newark, Del. D . H . Wilkins, General’ Electric Research laboratory, Schenectady, N . Y .
T
of papers presenting new or revised chemical methods of inorganic analysis continues to hold a substantial place in the international journals of analytical chemistry. Over 600 literature references were selected for examination in a n !&fort to discover significant researches in gravimetric and titrimetric analysis during the reporting period January 1962 to December 1963. Comments h a w been restricted to papers presenting essentially new quantitative inorganic chemical reactions, valuable interference studies or improvements in eFtablished analytical ~)rocedures,and important contributions to the theory of precipitation and titrimetric processes. I-nfortunately in some cases the original literature was not available and the reviewers were forced to depend on abstracts. ,lpologies are made f ’ x many worthwhile contributions to specific analysis problems which may not have been recognized. Significant Trends. I n spite of the efforts of chemists in all areas of analytical chemistry, technological advanccs continue to iresent analysis problcms for which there are no availablc answers. For this wason invcstigation of rcagerit structure and fundamrntal princii)l~~s of chemical rcartions must p r o c e d on a broad front. Reviews by ‘Relcher (240.4) and Irving and Pettit (Z40.t) stress the importance of specific f tinctional groups and steric hindrance i n metal chelate reactions. X-ray evid(2nce for the existence of Xi-Si boncing in the nickel dimethylglyoximate crystal lattice has been ronfirmed by lJan is and .1nderson (5.1). Hy comparison of the heats of solution of dimethylglyoxime and ethyl methylglyoxime nickel tihelates in noncoordinating solvents, the S i - ~ N i bond energy was estimated to be 10 kcal.1 mole. Fleischer and Freiser (44.1) attribute the large solubility difference between copper and nickel dimethylglyoximates to lack of (’u--Cu bonding and ease of hydration of the copper rhelate structure. I$y proton magnetic rwonanee measurement!; and potentiometrg, I%urger and R U T (16.1) found evidence of increased stability of metal dioxinies to hydro1 donar K bonding and geiimetrical ease of hydrogen bridge format ion. HE N U M B E R
Although “trial and error” remains the general rule in the development of new precipitants, titrants and indicat,ors, many research programs have followed a more systematic approach. Recent studies of 8-mercapto- (25.4) and 8-sulfamido quinolines (20~1) have revealed interesting differences in selectivity from 8-quinolinol. Irving and Pettit (l40.4) summarized their reasons for the failure of 2-methyl-8-quinolinol to precipitate aluminum in terms of decreased complex stability, lower reagent acidity, and increased solubility caused by the 2-methyl group. I n a n investigation of 5-nit’roso- and 5-nitroso2-methyl-8-quinolinols, Alduan (3d) observed no precipitation of aluminum with either compound. The relative sensitivity of these derivatives toward sulfide-forming elements as opposed to hydrous oxide-forming elements was attributed to acidity effects of the nitroso group rather than any steric hindrance of the 2-methyl group. Important contributions to nucleation theory have been reported by Nielson (89.4) and Kalton (233A). Many of the apparent inconsistencies in current theory may be explained by heterogeneous nucleation on foreign particles a t ion product concentrations above the solubility product but, beloiv the critical supersaturation value. Above the critical supersaturation point. rapid homogeneous nucleation occurs. Optimum crystal size is obtained with ion product concentrations a t or slightly below critical supersaturation. Walton and Hlabse (134.1) have shown that the rate constants for crystal growth of barium sulfate are essentially equal for excess barium or sulfate ions and the rate is surface rather than diffusion controlled. These conclusions have many implications Lvhich relate to precipitation of metal chelates from homogeneous solution. For example, Howick and Jones (51.1 62A) have obt,ained crystalline precipitates in quantitative yield by volatilization of solvent in much shorter time than most other PFHS techniques. A series of polyhydric alcohols and acids were arranged in order of masking e@ciency for precipitation separations by I’yatnitskii and Klibus 1201.1). Hulanicki (53.1) has expanded the masking selectivity ratio proposed by Cheng to include terms describing the proper-
ties of the salt, cation masking and anion masking. Complete masking of precipitation reactions requires a masking coefficient value less than 3 while complete demasking occurs a t 1111’ values greater than 5. Accurate predictions of optimum conditions for a specific separation may be derived if the eqiiilibrium constants are available. Sakagawa and Tanaka (84.4) have developed a quantitative mathematical treatment of exchange equilibria involving two metals, an indicator and chelometric titrant. Similar types of equations were applied by Kotrly (62.4) to evaluate optimum conditions for stepwise photometric titration of two metals with a chelometric titrant. The equations predict the improved linear end point step which results with moderate amounts of metallo-chromic indicator. All of these calculations suffer from the standpoint that only rapidly equilibrating systems may be properly described. The first chelon capable of forming stable 2 : 1 metal ligand chelates in a useful titrimetric reaction is described by PIibil and S’esely (62B, 64B). Triethylenetetramine .~,N,.L”,S”,S”‘,‘V”’- hexaacetate (T‘l“.i) forms 1: 1 chelates wit>h trivalent metals and 2 : 1 chelates with bivalent metals but there are a number of exceptions. A study of factors which determine coordination saturation with these exceptions should be very worthwhile. Progress continues to be made in the determination of acid indicator and metal ion-indicator dissociation constants. Corsini et al. (26.1) have measured the 1-(2-pyridylazo naphthol) (PAX) and 4-(2-pyridylazoresorcinol) (P-AR) complex constants with nickel, cobalt, zinc, and manganese. Koteinikov (61.1) reported the complex constants of 16 elements with 2-arsonophenylazo-4,5-dihydroxy -2,7-naphthalene disulfonic acid (.lrsenazo I ) . Information of this type is essential in order to make accurate preliminary calculations of pH, masking agent, and indicator to employ in a chelometric determination. Examples of sluggish chelometric titrations, blocking and antiblocking agents, and dragging indicator end points are well known to workers in the field. Significant progress has been made toward elucidation of variab!es VOL. 36, NO. 5 , APRIL 1964
381 R
responsible for these kinetic factors. Rogers, ;likens, and Reilley (104il)have investigated exchange kinetica of the copper-(ethylenedinitrilo) tetraace t ateEriochrom Blue Black-R system as a function of pH. Reaction of E D T A on copper Erio-R was found to depend on proton transfer which weakens the phenolic Erio copper bond by a SE2 mechanism. The rate of attack of Erio-R on copper E D T A was shown to involve ring formation between copper and Erio-R in the rate determining step. The latter rate is enhanced by mixed hydroxy-EDT-4 copper complexes. Two publications by Saito and Tsuchimoto (105-4, 106-4) discuss isotopic exchange of In114 tracer with E D T A and with N-2-hydroxyethylethylenediamine X,LY’,N’-triace t a t e (HEDTA). The exchange rate in both reactions was proportional to the concentration of a mixed hydroxo complex in alkaline solutions. Addition of a second ligand, such as glycine, markedly accelerates the exchange rate. A method of following relatively fast ligand exchange reactions by use of an ion exchange resin has been described by Margerum and Zabin (80d). It is not unlikely that nuclear magnetic resonance (NMR) techniques will find application to these kinetic problems which are so vital to further advances in the chelometric process.
PFHS method has received further study. Burriel-Marti and Vidan (16.4) showed that complete precipitation of molybdenum(V1) sulfide may be realized in 0.7M perchloric acid without pressure flasks and only two-fold excess thioacetamide. At lower acidities some reduction to molybdenum(V) occurs. Washizuka (1354) reports a different rate expression for precipitation of nickel sulfide in ammonia buffer compared to that given by Peters and Swift in the p H range 3 t o 6. The reaction was found to be base catalyzed by ammonia and hydroxide ion and independent of nickel concentration. Support for intermediate formation of thiolacetate in the alkaline hydrolysis of thioacetamide was presented by Cefola et al. (20A). They found that the rate of alkaline hydrolysis of pure thiolacetate is about one half that determined by Butler, Peters, and Swift in a study of thiolacetate formed from thioacetamide. Both groups found the activation energy to be 23 kcal./mole. An N M R investigation of the thioacetamide-hydrazine catalyzed reaction with manganese was described by Causey and Mazo (19=1). Induction times and rates of nucleation of manganese sulfide were determined by means of the effects of the paramagnetic manganese ion on the proton resonance signal. A manganese (11) hydrazine complex and estimate of
the solubility product of manganese sulfide are also reported. Soloniewicz (111A4)described the dense precipitate of bismuth sulfide formed by heating thiourea in acid solution. The rate of precipitation is much sloner than with thioacetamide because of the stable bismuth thiourea complex formed. Several studies of fractional precipitation of rare earth iodates have been presented. The use of talc as sites for nucleation was shown to yield improved separation of radioactive promethium on neodymium carrier from yttrium by Pruitt, Rickard, and Wyatt (99d). By combining slow production of iodate with induced nucleation, the relative supersaturation is maintained at a sufficiently low level that coprecipitation of the more soluble yttrium salt is markedly reduced. Firsching (41A) has described a double masking-cation displacement system capable of improved resolution of lanthanum and praseodymium. Treatment of approximately equimolar lanthanum-praseodymium mixture with equimolar molar diethylenetriaminepen taace t i c acid (DPTA) and HEDTA and dropwise addition of cadmium nitrate in the presence of potassium iodate at pH 5, results in selective displacement of lanthanum from its comparatively weak H E D T h complex. The combined masking agents worked better than
GRAVIMETRIC ANALYSIS
Precipitation from Homogeneous Solution. The number of metal chelates precipitated from homogeneous solution ( P F H S ) continues to grow. Recent reviews by Firsching (42A) and Gordon et al. (140A) describe precipitation by the technique of “in situ” synthesis. I t is clear that the method has many complex variables which require further definition. Studies of the rate of synthesis of dimethylglyoxime from biacetyl and hydroxylamine by Salesin, Abrahamson. and Gordon (107rl) and more recently by Hileman et al. (48;l) reveal many of the reaction intermediates and complexes which are involved in the precipitation of nickel. Supersaturation several hundred times that found with direct mixing of reagents was terminated by consecutive bursts of nuclei. Metal ion catalysis of the synthesis reaction was observed in precipitation of nickel dimethylglyoximate and copper 8-quinolinol. Wasrnuth and Freiser (136.1) postulatearate determining step in which hydroxide ion attacks a 1 : 1 copper (11) 8-acetoxyquinoline complex to explain the catalytic effect. Attempts to separate zinc or cadmium 8-quinolinates from nickel, cobalt or copper by slow cation release from ammonia complexes were unsuccessful
(4Sit).
Barium Copper
ANALYTICAL CHEMISTRY
Precipitation from Homogeneous Solution
Technique Volatilization of solvent Hydrolysis and cation release Hydrolysis
Volatilization of solvent Cation reduction Synthesis Magnesium Hydrolysis Volatilization of solvent Nickel
Volatilization solvent
Palladium
Synthesis
Thorium
Hydrolysis
Zinc
Hydrolysis
a
Metal sulfide precipitation by the 382 R
Table I.
Element Aluminum
--Indicates interference
Conditions 8-Quinolinol, acetone, pH 5.5. acetate buffer Sulfakic acid, EDTA, pH (2.0-3.0)
S-benzol I-,V-phenylhydroxylamineacetate, pH 4 5, acetate buffer, 65” C 8-Quinolinol, atetonechloroform, pH 5 5, acetate buffer SH4SCS, 0 2.11 HC1, X H D H HC1 Salicylaldehyde, SHiOH HC1, pH 2 9, IOK temp 8-.4cetoxyquinoline, pH 10, ammonia buffer, Ano C 8-&uin&oIj acetone, PH 9.6, ethanolamine buffer 8-Quinolino1, acetoneethanol, pH 5.2, acetate buffer Indane-l-one-2-oxime, XHZOH, pH 2.0, 25 hr. at 65” C., EDTA 8-Acetoxyquinaldine (200% excess), pH 5.0 8-Acetoxyquinoline, 2 hr., pH 4.5
Separationn Ca, Mgj Cd
Reference (50A )
Ca -Sr Co, Cd
(18A
Ca, Mg, Pb
(52.4
(35A )
Zn, Mn, Fe, Al, (88A Sn, Pb, Si Ni, Fe (93A -2 X ( F e ) S a , K, Ba -8 (Ca)
(24A
S a , K, 4X(Ba)
(49A
Mg, Ca
(51-4
Go, Fe,
(6A 1
many metals -Pt, AU Kot studied Pb, Ca, AIg -Cu, Mn
(lld)
(58‘4
each one separately. Reprecipit'ation of the lanthanum iodate resulted in a l)rel)aration of 98.59, purity and 70% yield. ,I summary of u:ieful quantitative precilitations by various P H F S methods are listed in Table I. Coprecipitation. The gross similarities betwren all the various multistage scparation techniques have been noted by many authorities. Tappmeyer and Pickett (1ZOA) have attempted quantitatively to compare the coprecipitation curve:, of copper, cobalt', molybdenum, and ca3dmium 8-quinolinates on phenolphthalein and pnaphthol carrier with the corresponding extraction curves of these chelates into chloroform. Employing equations and necessary constants analogous to those for extraction equilibria, calculated values of p H for one-half extraction were obtained which matched experimental results within 13.14 p H units. I3lock and Gordon (12-1) found that coprecipitat,ion of cerium(II1) and scandium on uranium(1V) oxalate precipitated from homogeneous solution follows a log distribution relationship. The change in distribution coefficient' value during the course of precipitation was attributed to a difference in degree of supersaturation. The log distribution law was also obeyed by the cadmiumzinc-thioacetamide syjtem in perchloric acid according to Tanigawa, Hasegawa, and Takiyama (119A). Coprecipitation of zinc was found to begin early in the precipitation of cadmium and increase rapidly near the stoichiometric point of complete precipitation. The fact that less coprecipitation occurs at' higher temperatures a,nd higher Zn/C,d ratios does not fit ii direct reaction mechanism which migit be advanced to explain the coprecipit.rtt'ion. Several radiotracer :studies have been performed to determine purity of precipitates. Barium sulfate was found to contain approximately 1% Ca4Swhen precipitated by slow hydrolysis of dimethyl sulfate (123A). Polyoxyethylene glycol has been rwommended as a surfactant in the separation of barium chromat,e from strontium (117A) and calcium oxalate from magnesium (I17A) using N-hydroxyethyl iminodiacetic acid (HEIDA) or glycine masking. Takamot0 claims the latter separation is superior to the P F H S method. Lakin and Thompson (66'4) obtained a 99.7y0 recovery of tellurium with gold or selenium collector when ccpper(I1) chloride was added to 4 to 6.V hydrochloric acid containing hypophosphorous acid. Tracer measurements using TeIz9 showed incomplete reduction of tellurium and carrier in the absence of copper salts. Merz (82.1) has reported a detailed study of the precipitation of molybdenum and tungsten with cinchonine using radio tracers. Quantitative
recovery of tungsten in 1 to 6JI nitric or hydrochloric acid is possible using this precipitant but molybdenum is about 1.5y0 low. Conditions were described for improved separation of tungstate from phosphate and arsenate but not molybdate using cinchonine and tannin together. An increasing number of selective preliminary separations of trace metals by sorption or cocrystallization have appeared in the literature. Vydra (132d) was able to recover microgram amounts of silver from gram quantities of copper, mercury, cadmium, zinc, nickel, bismuth, and iron(II1) masked with E D T A by sorption of the positive charged silver ammonia complex on a silica column at pH 8.5. Equally remarkable separations are described by Ziegler and eoworkers for isolation of gold on a silver sulfide-cellulose column (145A) and silver (144'4) or bismuth (146A) on a cadmium sulfide-cellulose column in the presence of lo4 times as much lead and other elements. Kuznetsov and Gorshkov (64A) and Weiss and Shipman ( 138A) have studied 8-quinolinol as a cocrystallizing agent under slightly different conditions. Uranium was quantitatively recovered a t dilutions of 1 part in 10" by use of phenolphthalein or p-naphthol as nucleation agents. Kuznetsov showed that complete recovery of uranium was not affected by EDT.4 masking of iron(III), aluminum and other metals. Weiss prefers to generate 8-quinolinol from 8-acetoxyquinoline a t pH 8.5 in the presence of small amounts of 8-quinolinol seed crystals. Cerium, praesodymium, and plutonium were quantitatively recovered among a large group of metals partially coprecipitated. relatively large percentage of metal 8-quinolinate is found in the first traces of precipitate indicating that metal ion concentration is occurring in the nucleation step. A summary of important considerations in selecting a cocrystallizing agent presented by Lai and Weiss (65'4, 137A) has some obvious similarities to those given by Tappmeyer and Pickett (12OA) but from a more restricted point of view. Ultramicro recoveries of silver and gold from sea water were studied by means of radio tracers employing thionalid and 2-mercapto-benzimidazole respectively as cocrystallizing agents. Thermogravimetry. A recent review of apparatus, techniques, kinetic studies, and applications of thermogravimetric analysis has been published by Coats and Redfern (22.4). Thermograms performed under externally controlled pressure or controlled atmosphere are described by Hurd (54.1). Simultaneouh differential thermal analysis and t hermogravimetric by 3Ic.ldie analysis, termed "I).i'l'X" (?SA), is claimed to yield better correlation of enthalpy and weight changes
than separate determinations. Langer and Gohlke (674) have combined the techniques of thermogravimetry and mass spectroscopy to aid in identification of complex pyrolysis products. Many of the discordant values for drying and decomposition t'emperatures in the literature are the result of a lack of standard methods of obt'aining and reporting thermogravimetric data. I n a recent letter, Newkirk and Simons (87*4) make specific suggestions which might help eliminate this source of difficulty. The thermogram of potassium acid phthalate was reexamined by Newkirk and Laware (86'4) in air and nitrogen atmospheres. The salt decomposes with loss of phthalic anhydride at 260' C. rather than 170", 190', and 236' temperatures reported b y others. I n a n oxygen-free atmosphere evidence was obtained for reduction of potassium carbonate to the metal. Pietri (SS.4) recommends P u ( S O ~ ) ~ . 4H20 while Miner, DeGrazio, and Byrne ( M A ) favor Cs?PuClc as a primary standard for plutonium. There is some question about the thermal stability of the tetrahydrate salt while care must be taken to wash the cesium salt with concentrated hydrochloric acid to prevent hydrolysis. Both of these compounds are superior analytical standards to plutonium metal. Thermal stability of nickel dimethylglyoximate formed by P F H S was examined under the electron microscope by Takiyama and Gordon (118A). A granular appearance in the surface structure noted at 120' C. gradually yielded small particles having the diffraction pattern of nickel oxide above 400' C. Eordner and Gordon (ISA) were unable to observe any difference in the thermograms of [UO~(Ox)~]HOx precipkated by direct mixing with 8-quinolinol and [r02(Ox)2]?HOx formed by hydrolysis of 8acetoxyquinoline which might shed light on the nature of these solvate compounds. The thermal stability of a number of metal 8-quinolinates have been reported by Charles (21A). Wendlandt and Horton (139A) have compared the differential thermograms of metal 8-quinolinate derivatives with the parent metal chelates. Very newly t,he same order of metal chelate stability was found by both investigations. The 5,7-dichloro-8-quinolinates appear to have slightly great,er thermal stability than corresponding metal 8-quinolinat,es. Further studies of this type should be profitable in determining which functional groups impart thermal stability to an organic reagent. Several interesting thermal analysis st,udies of high temperature acid-base fusion reactions have been recorded. Erdey and Gal (36.1) showed that sodium carbonate is superior to 110tassium carbonate in silicate fusions and large excess of calcium carbonate is not VOL. 36, NO. 5, APRIL 1964
383 R
required in the J. L. Smith method for alkalies. In many cases considerable reaction was found to occur a t a temperature below the melting point with optimum conditions reached a t 850' C. In a review of sodium peroxide as a flux for refractory oxides, Belcher @A) recommends 500' C. as the best compromise between adequate decomposition of samples and minimal attack on crucibles. Zirconium crucibles are found to be superior to porcelain, iron, and nickel for these fusions. The direct determination of calcite in bauxite by DT.l attempted by Paulik, Liptay, and Gal (91A) was only partially successful. High results were obtained because of overlapping thermal changes in the sample. Smith (210.4) has provided a simple method of regenerating spent magnesium perchlorate. Expanded vermiculite treated with saturated magnesium perchlorate solution and then dried a t 250' C. for 48 hours yields an excellent dessicant. In a comparison of 21 dessicants, Trusell and Diehl (1288A) have demonstrated again the superiority of anhydrous magnesium perchlorate over all other materials in drying efficiency.
borate occurs and above pH 5.5 some o ammonia may be lost. A 1 0 0 ~ excess of reagent is necessary for quantitative recovery of ammonium ion. Application of sodium rhodieonate to separate strontium from calcium a t p H 6-7 has been studied by Heitner-Wirguin and Albu (4YA). After removal of
Element Aluminum Barium
Beryllium
N-Nitrosophenylhydroxylamine Bismuth
Cadmium
GRAVIMETRIC DETERMINATION
A survev of new or modified gravimetric determinations of various elements is presented in Table 11. Brief discussion of those procedures which have received critical evaluation is included in the following paragraphs.
Alkali
Metals-Alkaline
384 R
Cerium
Earths.
Several studies of gravimctric methods for potassium have appeared. Tikhonov and Grankina (127.4) found the perchlorate method to be relatively free of interference from sodium, alkaline eart'hs, aluminum, titanium, and rare earths. The Cr/K and Fe/K ratios should be less than 0.6. h n x-ray diffraction and electron microscopy examination of dipotassium sodium hexanitrocobaltate(II1) by Belcher and Robinson (9.4) showed that the potassium content is variable depending on the Na/K ratio in the original solution. The compound is not suitable for accurate determination of potassium. I n addition to known cation interferences with the tetraphenylborate method for potassium, Thomas ( I 26.4) discovered that periodate and persulfate decompose the precipitant. Periodate produces low results while persulfate forms an insoluble product yielding high results. Crane and Smith (27:L) have carefully determined optimum conditions for ammonium ion preci1)itation with sodium tetraphenylborate. The solubility of the salt is essentially independent, of ionic strength in the pH range 1.5-3.1. Below pH 1 some decomposition of tetraphenylANALYTICAL CHEMISTRY
Reagent Salicylhydroxamic acid 8-Hydroxy-5,Tdinitronaphthalene-2-sulfonic acid Benzoylacetone
Copper
1-Phenyl-5-tetrazoline-5-thione Propylgallol
Conditions pH 6.5, dry, 110"
methylene-aaminopyridine NaCl Thiobarbituric acid
Table II. GraviSeparationa Reference Cu, Fe, Ti, V, $10 (97A) -Ga, Inb
pH 3, vac. dry
pH 9, EDTA, ("4)2C03, dry, 110" pH 5.8, EDTA, dry, 110' pH 3, dry, 110' 0.01M HS03, dry,
lloo P-Hydroxynaphthyl- pH 4.0, thiourea,
dry, 104'
Cu, Ni, Ca, Mg, Mn, Fe, AI -large FFe(III), AI, Ce, Th, Cu, Ni, Co, Zn, Cd -Ti(IV), U(V1) AI, Fe, Mg, Pb, U --A& Cu, Hg Zn, Cd, P,: Cu, As -(Sb, Sn) Co, Cu, Mg, Zn -Pb
(7lA
(29A
(115'
(141.4
(46A1
Conc.oHOAc, dry, 105
Zn, Co, Xi, Fe, Xln -Bi, Pb, Cu, Ag, Hg, T h -oxidants
(103-4
l-Hydroxy-3methoxy xanthen-9-one
Ce(IV), PH 3,0, ignite to oxide
Trivalent rare -(U, earths Th)b,Ti
(33A 1
Perimidine
pH 4.0, dry, 105"
-SO4-%, citrate Ag, Ri, Cd, Hg
-Pb, Sb, Sn N,!~r-Disalicj.lidine pH 11, XH3, EDTA4,S o interference
ethylenediamine Gallium
rhodizonate by anion exchange, the separated metals are determined by EDTA titration. Martin and Wagner (81A) describe an electrolytic method of destroying oxalate preparatory to precipitation of magnesium ammonium phosphate. Relatively large amounts of oxalate may be oxidized a t a graphite
N-Benzoyl N phenyl hydroxylamine Diantipyrinylmethane
F-, thiourea, dry, found 110" pH 2.5, dry, 110' Ce(III), Cu, Th,
vo*
(4565A1 (109A)
(28.4)
+2
-Tib, Fe(III), F Many metals (17.4) -Ti, Hg, Pt metals Germanium Quinoline-molybdic H?SO4, FeS04, dry, -(Po4-3, .ksO4C3)' (39.4 ) 150" many metals acid Indium iV-Benzoyl-NpH 5.0, KCN mask- Cu, Si, Zn (28.4 ) ing, dry, 110" -(Fe(III), Sn, Galb phenylhydroxylamine -po4-3, ~i Magnesium 2-Hydroxp-lpH 10, sulfosalicyl- Al, Fe, Zn (116A) naphthaldehyde ate, dry, 130" -large Cu and Mn Lead 3,5-lXbromopH 7-8, dry, 105' -Cd and other (1SOA) anthranilic acid bivalent metals Palladium 1,3-Dimethyl-4pH 1-3, dry, 105" Fe, I l n , Zn, Pt, Pb (14A) imino-5-hydroxysmall Os, Ir, Au iminoalloxan -Co, Yi, large Cu o-HydroxyacetopH 1, oxalate-tarCu, Xi, Co, Zn, Cd, (95-4) phenone oxime trate masking, Pb, Mn, small Pt, dry, 105" Au -(Fe, Sb, Bi, V, Ti)b Quinolinimide pH 1, citric acid, Many metals (76A) pyridine-2,3dry, 110' -Sn dicarboximide -EI>TA, c104-', tartrate 6M HCl, EDTA, volumetric finish
anode in 30 minutes ;tt 4 amps current while boiling with concentrated nitric acid is ineffective. .In excellent study of magnesium ammonium phosphate was published by Taylor, Frazier, and Gurney (121.1) who show that this compound dissolves incongruently with formation of M g 3 ( P 0 4 ~8Hz0. z Consid-
eration of this fact and attendant equilibrium reactions permit calculation of the correct solubility product value. These results also explain why the right precipitate composition is obtained using diammonium hydrogen phosphate but is in error when disodium hydrogen phosphate is employed.
metric Separation
Element Platinum Rubidium Rhodium Scandium
Selenium Silver
Tantalum Thorium
Titanium
Thallium I-ranium
Vanadium
Separation Reference Pd, Rh, AI, Fe, Co, ( l 4 7 A ) Xi, Cu -Br, I, Ir Li, Na, Ca, Mg, Fe, (75'4) 60% A41cohol, F1uorobo"ic acid AI, C1, SO,-', N03ice kath, dry, -CS, K 120 HC1, ignite in HB Ir, Ni, Fe (100A) Formamidine -large Cu sulfinic acid La, Y, T h b pH 2.9, dry, 120' m-Sitrohenzoic (65A -SOa-2, OAcacid Tetrachlnrophthalic pH 3, ignite to Thb (65A1 -Sa, K, Ce(IV), oxide acid R.E. Alk., .41k. E., R.E., (4.4) o-Hydroxyphenyl- pH 1, citric acid, Ti, Cd, Co, Cu, HzOa, dry, 120' phospl- oric acid Ni, Zn -2r. Th. In. TI -GO, --21 ' 2,3-Diaminonaph- pH 2, SaF, oxalated Many metals (7bA ? EDTA, dry, 110 -Ce(IV), Ti(1V) thalenc 7554 EtOH, dry, Sodium Zn, Cd, Cu, TI (34'4) 1loo -.V,LY-di( carboxymet hyl)anthranilo cu 3rate( IT) Pheny1ac:tohydrox- pH 4.0, oxalate, Xb (77'4) -Ti, Zr, citrate, ignite to oxide aniic acid tartrate pH 4, XH,OAC, Many metals (102'4) 3-Oximin iethylR.E., I-, AI, Fe, Cr salicyli acid ascorbic acid, -Zr, (Cu, ignite to oxide Ni)h R.E., U,Fe pH 4.5, ignite to 4-Hydroxy-3(56'4 -Ce( IV) oxide methoxybenzaldehyde Fe, R.E. (65.4, 4-Phenyl-4-methyl- pH 2.0, XH2OH HCI, ignite ti, -(W, Nb, T a ) b 90A ) i,%dihydroxyCe(IV), Zr, SO4-', oxide coumar in citrate, EDTA (112'4) Sodium hexathiopH 3 , 0", dry, 105' Cd, Cu, Zn cyanatochromate (111) I-Hydroxyxanth-9- pH 5, ignite t o Ce, La (52'4 -Ce(IV), Th, Sod-' oxide one pH 5.5, ?'If EI)TA, Ce, Ri, Pb, Th A\--Benzojl-LV(30'4 dry, 110 (Fe, Ti, M o , ZrIh p henylhydroxyl-Be, Cr, V, W, Famine o-Hyvdrox ,.acetopH 2.5, room temp., Fe (96d phenon? oxime H7P04, dry, 110" -Cu, Pd, Ti, F Reagent Hexamethonium chloride
Conditions pH 1, dry, 110'
I>iammonium 5 , s ' indigodisulfonate 5-p-Sitroiihenyl azosalicylic acid
pH 1, ignite to AI, Be, Fe, Ti, Ce, L,Co, Xi oxide pH 1, dry at 110" Many metals or ignite to oxide U, A1 -F-, CIO,-~, citrate pH 1, ignite to Fe, La, Ti, I:, Y oxide -Ce, Th, S04-a,
c&-'
Zirconium
2,3-IXhydroxynapht hdene-6siilfonic~acid
-1ndiwtes interferrnce. Intwferenw reiuovc,d by prior separation.
(2204-2,
citrate
Ohc-,
(57A) (98A)
(31.4)
Scandium Earths-Titanium Earths. The continuous supply of new reagents for scandium, titanium, and zirconium adds to the deluge of rather selective precipitants already available for this group of elements. However, most of the reagents reported are nonselective for members within the group. For example, Kuznetsov and hlimarin (639) describe separation of small amounts of scandium, titanium, zirconium, and thorium from large amounts of aluminum, beryllium, and rare earths with 1naphthalene-1-sulfinic acid in 0.25M perchloric or hydrochloric acid. Spacu et al. (113.4) have employed chloromandelic acid to determine yttrium in the presence of lant'hanum and cerium earths. The separation was markedly improved by addition of amino acids such as glycine which apparently inask rare earths but not yttrium. 13y use of suitable masking conditions (59'4) selective separation of titanium is possible using aT-benzoyl-.V-phenylhydroxylamine. Kaimal and Shome (60.4) found that a stoichiometric bis-AVbenzoyl-L17-phenylhydroxylamine titanium(1T') compound is formed in 0.05-V sulfuric acid at 65" to 75" C. which may be dried and weighed. Both MgEDT-1 and EDT.2 masking agents were required. Llajumdar and Bag (75A) recommend chelidonic acid in the presence of hydrogen peroxide to separate zirconium from titanium. Thorium, rare earths, and organic acids interfere. llajumdar and Pal (78.i) discovered during the course of research on the separation of titanium from niobium (77.4) that phenplacetylhydroxamic acid may be employed to separate titanium and zirconium from niobium. Both methods depend upon formation of soluble niobium(S') oxalate complexes at p H 4.0 and 6.5, respectively. Determination of hafnium and zirconium in the presence of each other has 'been improved. Tsuchiya (12QA) suggests titration of both zirconium and hafnium wit,h EDT.l in hot 0.9.U hydrochloric acid using Xylenol Orange indicator. The combined weight of mixed oxides is obtained by precipit,ation with mandelic acid and ignition to constant weight. N o interference was encountered from uranium(VI), iron(II), aluminum, zinc, manganese, and small amount's of titanium. Thorium was masked with sulfate. Stephen (114.1) has reviewed the application of niandelic acid and its derivatives for determination of zirconium. In another review on the determination of niobium and tantalum, Cockbill (23;1) stat,es that no gravimetric method is available which clearly separates these elements in one step. The S-benzoyl-;V-phenylhydroxylamine and 8-quinolinol methods are favored. VOL. 36, NO. 5 , APRIL 1964
e
385 R
Cadmium-Cobalt-Copper-Zinc.
h
fairly selrctive precipitation of cadmium with N,:\:-diallylthiocarbamoylhydrazine has been achieved by p H control and masking. Ahmed and Dhar (2-4) report quantitative separation of cadmium from copper, cobalt, mercury, nickel, and silver at pH 6.5 to 9.5 in the presence of cyanide. A critical study of tripotassium hexanitro cobaltate(II1) in acetic acid media was published by Lingane, Lingane, and Morris (70'4). Analysis of precipitates showed a K/Co rat'io of 2.87 indicating contamination with dipotassium tetranitrocobaltate(I1). 13y using optimum conditions and an empirical factor, this method is recommended as one of the best procedures for macro cobalt. Singh and Kumar (109il)describe precipitation of copper, nickel, bismuth, zinc, mercury(II), antimony(III), tin(II), and cerium(IV) with N,,V'-disaIicylidene (ethylenediamine) among some thirty different elements studied. However, only the copper(I1) complex is insoluble in the presence of ammonia tartrate, citrate, fluoride, thiourea, triethanolamine, and EDTA at, p H l l . Pirtea (34.4)has investigated the micro precipitation of copper and zinc bis(1,lOphenanthroline) and bis(2,2'-bipyridine) t,hiocyanat,es. This system yields stable salts of many bivalent transition metals in the pH range 3-6 in the presence of trivalent metals and alkaline earths. Macro amount,s of copper were collected on cadmium sticks from steel samples dissolved in hydrochloric or sulfuric acids. The method is recommended by Borun ( 7 A ) as a rapid preliminary separation procedure. Platinum Metals-Uranium. Little progress has been made in devising selective reagents for platinum metals other than palladium. Ziegler and Pape (147.4, 148A) have described precipitation of a number of hexamethonium complex salts which are sensitive but not very selehve. Milligram quantities of palladium can be separated from 10-fold amounts of indium, platinum, rhodium, and ruthenium with 8-quinolinol in acetate buffer according to Shlenskaya and Efimova ( I 0811) . Faye and Inman (37.t) describe a ncw fire assay procedure for rhodium using molten t,in. Tertipis and Beamish (124.I) have studied the concentrat,ion of iridium by t,heir iron coppernickel fire assay method. In both investigat,ions improvement over the c*litssic*al lead but,ton method was noted. The first critical comparison o f the determination of rhodium, iridium, platinum, and palladium by c,hemical and fire assay procedures was re1)orted by 'I'erti1)is and I3eamish (125.1). Only iridium was faun$ to be significmitly in error by the fire assay method.
386 R
ANALYTICAL CHEMISTRY
Complete precipitation of rhodium sulfide was obtained by a sealed tube reaction in mixed hydrochloric-perchloric acids with hydrogen sulfide. The procedure was devised by Maienthal (74il) to separate rhodium from uranium alloys. Vinogradov and hpirina ( 1 5 l A ) have restudied the hexammine cobalt (111) nitrate method for uranium(V1). They report no interference from aluminum, zirconium, molybdenum, vanadium(IV), small amounts of tungsten, or fluoride in ammonium carbonate solution masked with EDTA. The formula of uranium phosphate precipitated from nitric acid-ammonium sulfate solution is (UO) (YO2) PzO; rather than (LTO&Pz07. Wright, Hayes, and Ryan (143.4) reached this conclusion from thermograms and analysis data. Considerable success has been obtained in selective precipitation of various elements with Y-benzoyl-N-phenylhydroxylamine. h useful procedure for recovery of uranium from many metals has been devised by Das and Shome (SOA). Nonmetals. Tarasenko (122A) has determined mixtures of chloride, bromide. and iodide b y precipitation of silver salts followed by conversion of chloride to silver bromide with ammonia-potassium bromide and finally conversion of bromide to silver iodide with ammonia-potassium iodide. The composition of lead chlorofluoride has been examined as a function of method of formation. Winkler (142.4) found that the precipitate is contaminated with lead chloride and basic lead salts unless formed by slow addition of lead nitrate. ; i comparison of tetraphenylarsonium chloride with nitron for determination of hexafluophosphate by ;iffsprung and Archer (1-4) revealed some advantages of the arsenic compound. Among the possible contaminates only difluophosphate was found to interfere. By boiling with alkali, monofluophosphate is formed which does not precipitate. Several papers have described applications of the quinoline molybdate method originally proposed by Wilson. Filipov (58.4) has demonstrated that interference in the determination of phosphate may be reduced by addition of ammonium fluoride to complex silicon and hydrazine to reduce arsenic(V) to (111). The blue heteropoly acid formed was dried a t 150" C. h similar procedure using iron(I1) sulfate reluctant in the absence of fluoride wa5 employed for silicon (40.1). Lench (6S.t) prefers to volatilize arsenic( 111) bromide, 1)recipitate the quinoline molybdate acidi, and then extract the phosphorous complex with ammonia-acetone solvent. In this manner most of the difficulties caused by tungsten were overcome. X survey of organic precipitants for nitric acid by Salam and Stephen (140A) has recently been published.
TITRIMETRIC ANALYSIS
The current literature concerning titrimetric procedures continues to demonstrate the widespread use of chelometric titrations. Several new titrants have been described which are more selective than the more generally used EDTA. Application of selective titrants eliminates some masking problems; however, the commercial availability of these reagents limits their use. While many new studies have appeared since the last review it is disappointing to see the substantial number of papers which are repetitious in nature. Hypothetical analytical problems which if they actually occurred could be solved by any of a dozen published methods serve only to dilute the literature. Titrations employing coulometric, amperometric, potentiometric, or thermometric techniques are not included in this review.
Acid-Base and Precipitation Titrations. Underwood and Howe (87B) have studied kinetic problems in the titration of carbon dioxide solutions. The enzyme carbonic anhydrase provides a rapid reaction and the end point is determined by the ultraviolet absorption of the carbonate ion. The same end point technique permits titration of bicarbonate and carbonate as well as carbon dioside-bicarbonate and hydroxide-carbonate miltures Frank (36B)and Tereshko (86B)worked on the determination of boron in boron silicide and in borides using mannitol. .kidbase titrations using luminol and fluorescein in the presence of hydrogen peroxide were studied by Erdey, Pickering, and Wilson (29B). I t is proposed that luminol forms a transannular peroxide which catalyzes oxygen transfer to fluorescein and thus yields enhanced fluorescence. Reports of interesting precipitation titrations have appeared using a metallo chromic indicator. 13ismuth has been determined using the limited solubility of diantipyrinylmethane tetraiodobismuthate (92B). Potassium iodide, light petroleum, and ascorbic acid are added to a bismuth solution and the t i tration is performed with diantipyrinylmethane in 0.5N hydrochloric acid until the solution is colorless. The precipitate floats in the presence of light petroleum and does not interfere in the observation of the end point. Ascorbic acid serves to reduce iron(II1) and prevent the oxidation of iodide. No interference is reported by the presence of aluminum, manganese( [I), iron(II), zinc, alkali metals, or magnesium, or small amounts of barium strontium, calcium, cobalt(II), nickel, or chromium (111); cadmium, lead, and tin interfere. Interference due to copper (Cu Ni, Co (Fe, Cu) Th RI n
(55Bj 168Bi
tion of molybdenum (41B), tungsten (41B),or niobium (S9B)in fluoride media in the presence of iron has been accomplished by reduct’ionof aliquot samples with a Jones reductor and a silver reductor. Chelometric Titrations. Several polyarnino-,V-carbosylic acids have been used as selective reagents for titrations. Copper has been determined in the presence of a large number of cations using ethylenediamine iV,N,iV’, iV’-tetra-n-propionic acid (79B). Ethyleneglycol-bis(P-amino ethylether)N,N’-tetraacetic acid (EGTA) and ZnEGTA-PA4Nindicator have been used for the determination of calcium in the presence of magnesium (54B). Lassner (47B) proposed the determinat,ion of niobium(V) using nitrilotriacet,ic acid (STA) which forms a 1 : 1 complex with the perosyniobium(V) complex. Methyl Calcein is used as an indicator. I n prior work (48B) the titration of the titanium perosy-complex in t’hepresence of niobium and tantalum is described using diamino cyclohexane-AV,S,N’,N’tetraacetic acid (DCTA). Excess DCTA is back titrated with a standard copper solution a t pH 5-5.5 using Calcein or Methyl Calcein Blue as an indicator. DCTA has also been used for the titration of aluminum, chromium (111), and iron(II1) (61B, 65B). The successive determination of thorium and rare earths was studied by Pfibil (64B) using diethylenetriaminepentaacetic acid (DTPA) and triethylenetri:iminehesaacetic acid (TTHA). Some binary mixtures (62B) have been titrated using TTHA and EDT.4. Flaschka and Ganchoff ( S S B ) found cadmium in the presence of zinc with 1,2 - diaminocthosyethane - 3’,AV,X‘,X‘388 R
ANALYTICAL CHEMISTRY
tetraacetic acid using a photometric end point. Zinc (S2B) has been determined in the presence of cadmium by a method based on displacement of lead from its EGTA complex by cadmium. iifter precipitation of the displaced lead with sulfate, the zinc is titrated directly with EDTA. Lindstrom and Stephens (51B) suggest the use of magnesium iodate tetrahydrate as a primary standard for E D T A solutions. E D T A has continued t o be used in many circumstances. Table I11 lists procedures based on EDTA. The parentheses after the element give the matrix or elements present in the determination. A new photometric titration of beryllium described by Florence and Fawar (S4B) is remarkably free of interference. The sample is masked with escess DCTA or EDTA in the presence of hydrogen peroxide. Beryllium is complesed with excess sodium sulfosalicylate a t pH 10 which is back titrated with standard beryllium sulfate using Arsenazo indicator. Recent papers by Yamaguchi and Ueno (90B) have compared the masking properties of P-aminoethylmercaptan and P-mercaptopropionic acid with thioglycolic acid. Both reagents form nearly colorless complexes in contrast to highly colored thioglycolate complexes formed with many metals. Differences in masking action are small. Several papers have dealt primarily with indicators for chelometric titrations. Alizarin Acid Black SN has been suggested as an indicator for calcium at pH 11.512.5 (76B). Kirkbright and coworkers (4SB-45B) studied some fluorescent indicators. They suggest screening the residual fluorescence of Calcein W with acridine and Calcein Blue with Rhodamine B or fluorescein (44B). The blue fluorescence of 3,3’-dihydroxybenzidine-N,N,N’,N’-tetraacetic acid is quenched by copper and lead in the pH range of 4-10 (45B). Back titrations of EDTA with copper using the fluorescent indicator 4.4’-diamino~tilbene-N,N,~V’, K’-tetraacetic acid and its 2,2’-disulfonic acid were employed. Each fluoresce at pH greater than 4 and are quenched by various cations. Datta (RSB) reported 3-(6-sulfo-2-naphthylazo) - 4,5 - dihydrmynaphthalene - 2,7disulfonic acid @SXADXS-6) to be comparable to Xylenol Orange as an indicator for thorium. Xylenol Orange has been wed in a microdetermination of zinc (fB)in the presence of copper by masking with thiosulfate. Lyle and Rahman (52B) investigated a number of indicators for the direct titration of yttrium and the lanthanons. Xylenol Orange a t a pH of 5.8-6.4 was preferred over Alizarin Red S screened a i t h Methylene Blue, Eriochrome Black T and copper naphthylazoxine.
LITERATURE CITED GRAVIMETRIC
(1A) Affs rung, H. E., Archer, V. S., ANAL.&HEM. 35, 1912 (1963). (2A) Ahmed, A. D., Dhar, S. N., Sci. Cult. (Calcutta) 28, 540 (1962). (3A) Alduan, J. A,, Rev. Acad. Cienc. Exact., Fm-Quam. Sat. Zaragoza 15, 41 (1960); P A . 59, 14549f (1963). (4A) Alimarin, I. P., Fadeeva, V. I., Acta Chim. Acad. Sca. Hung. 32, 171 (1962); C..4. 5 8 , 6 1 8 5 ~(1963). (5A) Banks, C. V., Anderson, S., J . Am. 84, 1486 (1962). Chem. SOC. (6A) Bark, L. S., Brandon, D., Talanta 10, 1189 (1963). (7A) Borun, G. A,, ANAL. CHEM.34, 720 (1962). (8A) Belcher, C. B., Talanta 10, 75 (1963). (9A) Belcher, R., Robinson, J. W., Anal. Chim. Acta 27, 568 (1962). (10A) Billman, J. H., Chemin. R., ANAL. CHEM.34, 408 (1962). (11A) Billo, E. J., Robertson, B. E., Graham, R. P., Talanta 10, 757 (1963). (12A) Block, J., Gordon, L., Ibid., 10, 351 ilSfi3). --, (13Aj Bordner, J., Gordon, L., Ibid., 9, 1003 (1962). (14A) Burger, K., Acta Chim. Acad. Sci. Hung. 26, 305 (1961); C.A. 55, 23178h (1961). (15A) Burger, K., Ruff, I., Talanta 10, 329 (1963). (16A) Burriel-Marti, F., Vidan, A. M., -4nal. Chim. Acta 26, 163 (1963). (17A) Busev, A. I., Skrebkova, L. M., Zh. Analit. Khim. 17. 56 (1962): C.A. 57. 5294d 11962). (18A) Cartwtight,’ P. F. S., Analyst 87, 163 (1962). (19A) Causey, R. L., Mazo, R. M., ANAL. CHEM.34, 1630 (1962). (20A) Cefola? M., Peter, Sr. S., Gentile, P. S.. Celiano. A. V.. Talanta 9. 537 (1962). (21A) Charles, R. G., Anal. Chim. Acta 27, 474 (1962). (22A) Coats, A. W., Redfern, J. R., Analyst 88, 906 (1963). (23A) Cockbill, M. H., Ibid., 87, 611 (1962). (24A) Corkins, J. T., Pietrzak, R. F., Gordon, L., Talanta 9, 49 (1962). (25A) Corsini, A , , Fernando, Q.) Freiser, H., ANAL.CHEM.35, 1424 (1963). (26A) Corsini, A,, Yih, I., Fernando, Q., Freiser, H., Ibid., 34, 1090 (1962). (27A) Crane, F. E,, Smith, E. A,, ChemislAnaljpt 52, 105 (1963). (28A) Das, H. R., Shome, S. C., Anal. (‘him. Acta 27, 545 (1962). (29A) Das, J., Banerjee, S., 2 . Anal. Chem. 189, 183 (1962). (30A) Das, J., Shome, S. C., Anal. Chim. Acta 27, 58 (1962). (31A) llev, B., Jain, B. Current Sci. (India) 32, 306 (1963). (32A) Ilev, B., Jain, B. 11, Proc. Indian Acad. Sci. 54, 341 (1961). (33A) Ibid., 55, 313 (1962). (34A) I>ragulescu, C., Simonescu, T., Anton, R., ilcad. R e p . Poprilare Romine, Baza Cercetari Stiint. Timisoara, Studii Cercetari Stiinte Chim. 8, 191 (1961); C..4. 57, 1540f (IOV2). (35A) Ellefsen, P. R., Go;don, L., Belcher, R., Jackson, W . G., lalanta 10, 701, 703 (1963). (36A) Erdey, L., Gal, S., Ibid., 10, 23 \ - -
IIRHX~. \ - - - - I
(37A) Faye, G . H., Inman, W.R., Ax.11.. CHEM.34, 972 (1968). (38A) Filipov, I)., (’ompt. I h d . Scad. Hulgare Scz. 14, 687 (196l), 56, 14923h (1062).
(39A) Ibid., 15, 281 (1962); C . A . 57, 14426a 11962). (40A) Ibid., hfashincstroene (Sofia) 10, 17 (1961);,C.A. 57, 4035g (1962). (41A) Firsching, F. H., ANAL. CHEM. 34, 1696 (1962). (42A) Ibzd., Talanta 10, 1169 (1963). (43A) Firsching, F. H., Brewer, J. G., ANAL.CHEM.35, 1030 (1963). (44A) Fleischer, D., I'reiser, H., J . Phys. Chem. 66, 389 (1962). (45A) Golubovit, V . B., Vitorovi6, O., Saper, R. P., Glusnak Hem. DruStva, Beograd 25-26, 535 (1960-1); C . A . 59, 3303f (1963). (46A) Gusev, S. I., Pesis, A. S., Zh. Analzt. Khzm. 17, 844 (1962); C . A . 58, 7355c (1963). (47A) Heitner-'A-irguin, C., Albu, A,, Talunta 9, 79 (1962). (48A) Hileman, 0. E., Ellefsen, P. R. Magee, It. J., Gordon, L., Ibid., 10, 419 (1963). (49A) Howick, L. C., Ford, X . L., Jones, J . L., Ibid., 10, 193 (1963). (50A) Howick, L. C., Jones, J . L., Ibid., 9, 1037 (1962). (51A) Ibid., 10, 189 (1963). ( 5 2 A ) Ibid., p. 197. (53A) Hulanicki, A.,I'bid., 9,549 (1962). (54A) Hurd, B. G., AXAL. CHEM. 35, 1468 (1963). (55A) Jain, B. D., Siiigh, H. B., Indian J . ('hem. 1, 317 (1963). (56A) Jain, B. D., Singh, J . J., Anal. C'him. Acta 27, 359 111962). (57A) Ibid., J . Less Common Metals 4, 145 (1962). (58A) Jones, J. P., Hileman, 0. E., Gordon, L., Talanta 10, 111 (1963). (59A) Kaimal, V. R. M., Shome, S. C., Anal. Chim. Acta 27,298 (1962). (60A) Ibid., 29, 286 (1963). (61A) Koteinikov, F., Zavodskaya Lab. 28, 1179 (1962). (6JA) Kotrly, S., A n d . Chim. Acta 29, 552 (1963). (63A) Kuznetsov, D. I., Alimarin, I. P., I r v . Vysshikh Ucheb. Zavednii, Khim. i Khim. Il'ekhnol. 5 , 26 (1962); C . A . 57, 40'28f (L962).
(64.4) Kuznetsov, V. I., Gorshkov, V. V., liadiokhimiya 5 , 93 (1963); C.A. 59, 34557d (1963). (65A) Lai, M. G., Weiss, H . V., ANAL. CHEM.34, 1012 (1963). (6(iA) Lakin, H. W., Thompson, C. E., 1.. S. Geol. Survey, Prof. Papers N o . 450 E. I28 119621. (67A) Linger; H . ' G., Gohlke, R. S., ANAL.CHEM.35, 1301 (1963). (68A) Lench, A.,Ibzd., 35, 1695 (1963). (69A) Liang, 8. C., Hung, S. C., Hua Hsueh Hsueh Pao 28, . 12, , 139 (1962). (70A) Lingane, J . J., Lingane; P. J., Morris, J I . D., Anal. Chim. Acta 29, 10 (1963). ( 7 1 A ) Liu, S. L., Yin, T. C., Hua Hsueh Hsueh Pao 28, 20 (1962); C.A. 59, 1 2 1 5 8 ~(1963). (72A) Lott, P. F., Cckor, P., Moriber, G., Solga, J., AXAL CHEM.35, 1159 (1968). (73A) AlcAdie, H. G., Ihid., 35, 1840 (1963). (74A) Llaienthal, E. J., Ibid., 35, 1094 (1968). (75A) Majumdar, A. K., Bag, S. P., A n a l . ('him. Acta 28, 293 (1963). ( 7 6 A ) Ibid., Z . Anal. Chem. 186, 347 (196%). (7iA) Majumdar, A . K., Pal, B. K., .Anal. ('him. Acta 27, 356 (1962). (1XA4)I b i d . , 29, 168 (1963). ( (9.4) Xlaksiniycheva, 2:. T., Maslentsova, 'Y. .4., Suleinianova, F. E.,Zai'odskaya Lab., 27, 667 (1961); C.A. 56, 4086h (196%). (80A) Alargerum, 11. 'V., Zabin, B. *A., J . Phys. Chem. 66, 2214 (1962). '
(81A) Martin, J., Wagner, W., Talanta 9. 265 (1962). (82A) Merz, E., Z . Anal. Chem. 191, 416 11962). (83A) Miner, F. J., DeGrazio, R. P., Byrne, J . T., Anal. Chem. 35, 1218 119631. (84A) gakagawa, G., Tanaka, AI., Talanta 9, 847, 917 (1962). (85A) SBscutiu, I., Ngscutiu, T., Rev. Chim. (Bucharest) 13, 163 (1962); C.A. 57, 10518s (1962). (86A) Newkirk, A. E., Laware, R., Talanta 9, 169 (1962). (87A) Xewkirk, A. E., Simons, E. L., Ibid., 10, 1199 (1963). (88A) Newman, E. J., Analyst 88, 500 fl963). \----,
(89A) Nie Nielson, A. E., ilcta Chem. Scand. 15, 441 (1961). (90A) Patrovsk9, V., Collection Czech. Chem. Commun. 27, 1824 (1962). (9fA) Paulik, F., Liptay, G., Gal, S., I'alanta 10. 10, 551 119631. (1963). (92A) Pietri, C. E., ANAL. CHEM.34, 1604 (1962). 160 (93A) (93-4) Pietrzak, R. F., Gordon, L., Talanta 9, 2327 (1962). ((94A) 94A 1 Pirtea, T. I., Mikrochim. Acta 5 , 813 (1962). (95A) Poddar, S. S . , Anal. Chim. Acta 195A) 28. 28, 586 (1963). 196Aj (96A) Ibid., J . Indian Chem. SOC. 40, ' 766 706 (1963). (97A) Poddar, S. N., Sengupta, N. R., Adhya, J. S . , Sci. Cult. (Calcutta) 29, 258 (1963). i i a m ~ 198A) Poua. G.. Baiulescu. G.. Moldoreanu,' J., Rev. Chim. ' Acad. Rep. Populazre Roumazne 7 , 375 (1962); C.A. 59, 2164c (1963). (99A) Pruitt, M . E., Rickard, R. R., Wyatt, E. I., ANAL. CHEM.34, 283 (1962). (100A) Pshenitsyn, PIT. K., Prokofkva, I. V., Bukanova, A. E., Zh. Analzt. Khzm. 18, 761 (1963); C.A. 59, 8115h .
I
II96X) \ - - - - ,
(101A) Pyatnitskii, I. V., Klibus, A. K., V k r . Khim. Zh. 29, 245 (1963); C.A. 59, 3298d (1963). (10JA) Ray, A . R., Anal. Chem. Acta 28, 580 (1963). (103A) Ristici, J., Acad. Rep. Populare Komine Bum Cercetari Stiint. Timisoara, Studii Cercetari Stiinte Chim. 9, 41 (1962); C.A. 58, 2833h (1963). (104A) Rogers, D. R.,Aikens, 11. A,, Reilley, C. X., J . Phys. Chem. 66, 1582 (1962). (105A) Saito, K., Tsuchimoto, RI., Bull. Chem. SOC.Japan 36, 1073 (1963). (106A) Ibid., J . Inorg. Sucl. Chem. 25, 1245 (1963). (10iA) Salesin, E. D., Abrahamson, E. W., Gordon, L., Talanfa 9, 699 (1962). (108A) Shlenskaya, V. I., Efimova, V. G., Vestn. Moskov. Univ., Ser. 11: Khim. 4, 56 (1962); C.A. 57, 157972 (1962). (109A) Singh, B. R., Kumar, S., 2. Anal. Chem. 185, 211, 259 (1962). (llOA) Smith, G. F., Talanta 9 , 6 5 (1962). (111A) Soloniewicz, R., Chem. Anal., Warsaw 7, 626 (1962); C.A. 57, 11846e (196%). (112.4) Spacu, P., Balanel, E., Analele Univ. C. 1. Parhon," Ser. Stiint. S a t . 9, 51 (1960); ( ' . A . 58, 7367~(1963). (113A) Spacu, P., Rlavrodln, ll.,Antonescu, E., Serban, S.,Acad. Rep. Popidare Iiomine, Studii Cercetari C'him. 10, 357 (1962); ( ' . A . 59, 1067c (1963). (114A) Stephen, iV. I., Ind. Chem. 38,429 (1962). (115A) Stevancevic, D. B., Bull. Boris Kidric Inst. Sucl. Sei. 14, 67 (1963): C.A. 59, 1 0 7 4 8 ~(1963). 1116A) Struganova. A. M..Tr. Pernzsk. J l e d . InsL 31, 169 (1961); C.A. 56, 6653b (1962).
(11iA) Takamoto, S., J . Chem. SOC. Japan, Pure Chem. Sec. 81, 1539, 1542 (1960). (1184) Takiyama, K., Gordon, L., Talanta 10, 1165 (1963). (119A) Tanigawa, Y., Hasegawa, S., Takiyama, K., Bunseki Kagaku 11, 1300 (1962); C.A. 58, 6177b (1963). (120A) Tappmeyer, W.P., Pickett, E. E., AXAL.CHEM.34, 1709 (1962). (121A) Taylor, A. W.,Frazier A. W., Gurney E. L., Discussions Faraday SOC. 59, 1580 (1963). 11224) Tarasenko. I. M . I.. T r . 1-90 1-00 (1224) Tarasenko, I., Tr. (Peruogo) X o s k . Med. Ins't. Inst. -17, 17, -164 194 (1962): C.A. 60, 12d (1964). (123A) Terentev, A. P., Litvin, K. I., Rukhadze, E. G., Zh. Analzt. Analit. Khim. 18, 406 (1963); C . A . 58, ll94lh (1963). (12411) Tertipis, G. G., Beamish, F. E., ANAL.CHEM.34. 108 11962). (125A) Tertipis, G. G., 6., 'Beamish, F. E., Talanta 10, 1139 (1963). (126A) Thomas, J. D. R., Analyst 87, 151 11967) (1962). ,- --,. (127A) Tikhonov, V. S . ,Grankina, M .Y., Zh. Analit. Khim. 17, 917 (1962). C.A. 58. 58, 11952~11963). (1963). (128A) Trusell, F.', F., Diehl, H., ANAL. CHEM.35, 674 (1963). (129A) Tsuchiya, Y., Runseki Kagaku 11, 1176 (1962): C.A. 58, 2837e (1963). (130A) Vasilescu, C., Spineanu, A , , Rev. Chim. (Bucharest) 12, 735 (1961); C . A . 57. 11851h 119621. (131.4) V h g r a d o v , AI+., Apirina, R. M., Zh. Analit. Khim. 17, 222 (1962); C.A. 57, 409 (1962). (132A) Vydra, F., Tahnta 10, 753 (1963). (133A) Walton. A . G.. Anal. Chim. Acta 29. 434 119631, (134A) Wdton,'A. G., Hlabse, T., Ibid., 1
29. 249 1 1963). \ - -
- z
(135.k) %'ashizuka, S., Runseki Kagaku 12, 20 (1963); C . A . 58, 10707f (1963). (136A) Wasmuth, C. R., Freiser. H.. Talanta 9, 1059 (1962). 37A) Weiss, H. V., Lai, M.-G., Anal. Chim. Acta 28, 242 (1963). 38.4) Reiss, H. V., Shipman, W. H., ANN.. CHEM.34, 1010 (1962). 39A) Wendlandt, W. W., Horton, G. R., Ibid., 34, 1098 (1962). 40.4) West, P. R.,ILIacDonald, A. M. G., West, T. S.,eds., "Analytical Chemistry 1962, Proceedings of International Symposium, Birmingham University," Relcher, F. J., p. 107. Irving, H., Pettit, 11. L., p. 121: Banks, C. V., p. 131; Gordon,. L., Haberman, N.; Hileman, 0. E., Ellefsen, P., p. 145; Salam, S . A,, Stephen, W. I., p. 156; Elsevier, New York, 1963. (141.4) Wilson, A. I)., Lewis, D. T., Analyst 88, 585 (1963). (142A) Winkler, P. E., Bull. SOC.Chim. Relges 70, 690 (1961); CA 58, 283% (1963). (143.4) Wright, J. S., Hayes, T. J., Ryan, J. A . , .\'atrue 190, 1188 (1961). (144A) Ziegler, hl., Gieseler, hl., 2. Anal. ('hem. 191, 122 (1962). (14.iA) Ziegler, M.,Matschke, H. D., I b i d . , 191, 188 (1962). (146A) Ziegler, M., Myatha, M., Ibid., 196, 81 (1963). (147A) Ziegler, RI., Pape, G., Ibid., 191, 181 (1962). (148A) Ibid., 196, 241 (1963). I
,
TITRIMETRIC
(le)Ashton,
A . A , , Anal. Chzm. Acta 28, 296 (1963). ( 2 s ) BakBcs-Pol&, E., 2. Anal. Chem .__- - . 190,373 ( I Y W L ) . (3B) Bassett, J., ilnalyst 88, 238 (1963).
(4B) Berka. A.. Vulterin. J.. Z$ka. J.. Chemzst-Analyst 51, 24 11962). (5B) Ibzd., p. 88. VOL. 36, NO. 5, APRIL 1964
389 R
390 R
ANALYTICAL CHEMISTRY
