separate infrared quantitative analysis was performed on the contents of each tube in the fraction collector. LITERATURE CITED
(1) American Petroleum Institute, Research Project 44, Carnegie Institute of Technology, Pittsburgh, Pa. ( 2 ) Anderson, J. A., Jr., Seyfried, W. D., ANAL.CHEM.20, 998 (1948). (3) Bellamy, L. J., “The Infra-red Spectra of Complex Molecules,” pp. 26, 34, 47, 50, Wiley, Sew York, 1958. (4) Binder, J. L., ANAL.CHEY.26, 1877 (1954). (5) Estep, P. A., Karr, C., Jr., Appl. Spectry. 16, 167 (1962).
(6) Friedel, R. A., U. S. Bureau of Mines, Pittsburgh, Pa., private communication. 1956. (7) Hampton, R. B., ANAL.CHEM.21, 923 (1949). (8) Harvey, SI. C., Ketley, A. D., J . Appl. Polymer Sci. 5 , 247 (1961). (9) Jones, R. N.. S.neclrochim. Acta 9. 235 (1957). (10) Jones, R. N., Sandorfy, C., in “Technique of Organic Chemistry,” A. Weissberger, Ed., Yol. IX, Chap. IV, Interscience, New York, 1956. (11) McMurry, H. L., Thornton, V., ANAL.CHEM.24, 318 (1952). (12) Richardson, W. S., J . Polymer Sci. 13, 229 (1954). (13) Richardson, W. S., Sacher, A., Ibid., 10, 353 (1953). I
(14) Saier, E. L., Cousins, L. K., Basila, M.R.ANAL.CHEM.35. 2219 (1963). (15) Saier, E. L., Pozefsky: A., Coggeshall, N. D., Ibzd., 26, 1258 (1954). (16) Silas, R. S., Yates, J., Thornton, V., Ibid., 31, 529 (1959). PATRICIA A. ESTEP CLARENCE KARR,JR.
.
Morgantown Coal Research Center U. S. Bureau of Mines Department of the Interior Morgantown, W. Va. Division of Analytical Chemistry, 147th Meeting, ACS, Philadelphia, Pa., April 1964.
Complete Gas Chromatographic Analysis of Fixed Gases with One Detector Using Argon as Gas Carrier Addendum SIR: Since the publication of my article ( 2 ) previous articles by Hernandez, Strand, and Vosti, (1) and by Murakami (3) have come to my attention. I regret that these two articles were not included in my original bibliography. Both Vosti, e t al. and Murakami use two detectors, each equipped with a single filament. I n the analysis of fixed
gases the filaments of these two cells serve as opposing variable resistances in a bridge circuit. One cell is placed at the exit of the silica gel column and the second cell after the molecular sieve column. As a gas component is detected by either filament the recorder deflection is maintained in the same direction by a polarity reversing switch.
LITERATURE CITED
K.H., Strand, J. B., Vosti, D. C., Food Technology 15, 29 (1961). (2) Manka, D. P., ANAL. CHEY.36, 480 (1964). (3) Murakami, Y., Bull. Chem. SOC. Japan 32, 316 (1959); C. A . 54, 3045d (1960). DANP. MAKKA Graham Research Laboratory Jones & Laughlin Steel Corp. Pittsburgh 30, Pa.
(1) Hernandez,
Time Dependence of A.C. Polarographic Currents An Exchange
of Comments
SIR: Hung and Smith (6) have reported preliminary theoretical and experimental results concerned with the dependence of a.c. polarographic currents on drop time. We wish to point out that we have presented (1) a numerical analysis of Matsuda’s equation for the a x . polarographic wave ( 8 ) , and have indicated that under quasireversible conditions the current at the summit potential is drop-time dependent. Senda (IO) has discussed the time dependence of a.c. polarographic currents and has suggested its use to distinguish between quasi-reversible and reversible electron transfer reactions. We have shown also that this drop-time dependence for the quasireversible case may be predicted from a treatment based upon that of Breyer and Bauer ( 2 ) . Electrode-surface concentrations- of oxidant and reductant were derived using a quasi-steady-state approach (4, 12) and the results for the 22 18
ANALYTICAL CHEMISTRY
a.c. polarographic wave compare favorably with those of Matsuda ( 8 ) . Also, we have derived an equation for the a.c. polarographic wave in the case where a fast, irreversible, monomolecular, chemical reaction follows a reversible electron transfer reaction. The current decreased with increasing drop-time (1). Using this equation, we have measured the rate constant for the formation of the cadmium-EDTA complex by oxidation of cadmium amalgam in EDTA solution. Our results compare well with that of Koryta and ZAbransk$ (7) who used the shift in d.c. polarographic half-step potential to obtain their result. The rate constant for the substitution of calcium ions in the europium(I1)EDTA complex, formed by reduction of the europium(II1)-EDTA complex, has also been measured by a x . and d.c. polarography, The two methods do not
give the same result, and the phase angle measurements indicate that a double-layer effect is responsible for the discrepancy. One of us, with Florence (5j, has reported drop-time dependence of the a x . polarographic current for the reduction of 5-sulfo-2-hydroxybenzeneazo-2-naphthol. It was suggested that the mechanism of the reduction involved disproportionation of the hydrazo species. We have observed numerous other cases of drop-time dependent, a x . polarographic currents. In all of these, the electrode-surface concentration of the oxidant or the reductant is subject to a mass transfer process other than, or combined with, diffusion. The references quoted below refer to the papers in whichthis has been established. For example, the a.c. polarographic wave height for the reduction of aquo cadmium ions formed by dissociation of
(5) Florence, T. M.,Aylward, G. H., Australian J . Chem. 15, 65 (1962). (6) Hung, H . L., Smith, I). E., ANAL. CHEM.36, 922 (1964). ( 7 ) Koryta, J., Ubranskf, Z.,CollectLon Czech. Chem. Commun. 25, 3153 (19GO). (8) Matsuda, H., 2. Elektrochem. 62, 977 (1958). (9) Schmid, R. W.,Reilley, C. N . , J . Am. Chem. Soc. 80, 2087 (1958). LITERATURE CITED (10) Senda, SI., Kagaku no Kyozkz, “Zokan 50,” 15 (1962). (1) Aylward, G. H., Hayes, J . W., (11) Strehlow, H., von Stackelberg, Il., Tamamushi, R., “Proceedings of the Z. Elektrochem. 54, 51 (1950). First .4ustralian Conference on Elec(12) Tanaka, K,,Tamamushi, li., Bull. trochemistry 1963” J. A . Friend and Chem. Soc. Japan. 22, 187 (1949). F. Gutmann, eds., Pergamon Press, (13) Tanaka, X., Tamamushi, K., Oxford, 1964, in press. Kodama, M., 2. Physzk. Chem. S . F . ( 2 ) Breyer, B., Bauer, H. H., “Alternat14, 141 (1958). ing Current Polarography and Ten(14) Testa, A,, Reinmuth, W .H., AKAL. sammetry,” chap. 2, Interscience, Kew CHEM.32, 1512 (1960). York, 1963. GORDON H. AYLI\ARD (3) Breyer, B., Beevers, J. R., Bauer, JOHN W.HAYES H. H., J . Electroanal. Chem. 2, 60 School of Chemistry (1961). University of New South Wales (4) Eyring, H., Marker, L., Kwoh, T. C., J . Phys. Colloid Chem. 53, 1453 (1949). Kensington, Australia
the cadmium-EDTA complex (13) increases with increasing drop-time. Disproportionation of uranyl(V) ions formed by reduction of uranyl(V1) ions (3) causes the wave height to decrease with increasing drop-time. The hydrolysis of p-benzoquinone imine formed by oxidation of p-aminophenol ( 1 4 ) produces a decrease in the a x . polarographic wave height with increasing drop-time. Streaming a t the surface of the dropping electrode (11) causes a slight drop-time dependence of the wave heights for the reduction of amalgam-forming metal ions and for the oxidation of amalgams. Slow adsorption of film-forming surfactants (9) results in a decrease in a x . polarographic wave height with increasing drop-time. Of 10 substances tested, which exhibit tensammetric waves, only the wave for
camphor is time dependent. The adsorption of camphor a t a dropping mercury electrode is a slow process (9). Publications, describing full details of the experimental results, are in preparation now.
SIR: We would like to comment briefly on the correspondence of Aylward and Hayes and outline some recent experimental results obtained in these laboratories. Since publication of our recent communication (S), we have examined a number of systems exhibiting timedependent a x . polarographic currentsi.e., currents dependent on mercury column height. We undertook this work with the hope of being able to interpret correctly the effect in question so that it could be employed usefully in elucidation of electrode reaction mechanisms. I n this regard we find encouraging the results reported by Xylward and Hayes, as well as our own. The experimental observations of Aylward and Hayes, combined wit’h those we report here, certainly substantiate the existence and frequent occurrence of time-dependent a x . polarographic currents. The results also support the qualitative theoretical conclusion that mercury column height dependence will be observed in a x . polarography when some process in addition to diffusion is influencing kinetically the d.c. polarographic process (3). Table 1 lists systems we have studied, together with a statement indicating whether the alternating current amplitude and/or phase angle exhibited column height dependence. Systems 1, 2, and 3 involve simple diffusion controlled d.c. waves (1, 3, 8, 9). The lack of time dependence is in accord with expectations. Slow charge transfer influences the d.c. waves in systems 4 to 13 (1, 8, 10, 11). Results for system 4 are in excellent agreement with hfatsuda’s theory (3, 6 ) . The form of the time dependence for systems 5 to 13 deviates from Matsuda’s predictions for the simple quisi-reversible case, indicating more complicated processes. The time-dependent phase angles
indicate the possibility of multistep charge transfer, second order chemical reactions or adsorption (3). Vlcek’s proposal (11) that the europium reduction involves a mechanism of the type
0
accord with expectations for a mechanism involving disproportionation (5, 7’). Systems 20 and 21 yield data in qualitative agreement with theory for the familiar mechanism
+ e F= R1
e
Y e0
The catalytic process occurring in systems 22 and 23 exhibits a column height dependence in fair accord with expectations for the simple mechanism
R2
may explain the observations with europium. The results with zinc and bismuth may indicate step-wise charge transfer ( 4 ) . Systems 15 thru 23 involve a d.c. wave influenced by coupled chemical reactions (4,5 , ‘7, 9). The results for the uranium system seem in
Table I .
O+ne=R
?
I
Systems Studied
++
( a ) 6 0 X 10-3M UOzc2 0 30.V KC1 0 20M HCl ( b ) 3 0 X 10-3M UOZiz 0 30M KC1 0 20M HC1 (16) Ti(II7)/Ti(I1I) 0 20M H2C204 0 50M (NH4)20 0 0 0 0 0
1
Data for systems 16-19 might be explained by postulating that the reduction mechanism is
Redox system Supporting electrolyte (1) Fe(III)/Fe(II) 0 50M KzC204 ( 2 ) Ti(IY)/Ti(III) 0 20M H2C204 (3) Cr(CS)6-4/Cr(CN)G-3 1 O M KCN 1 O M &SO4 ( 4 ) 1(III)/T(II) (5) Eu(III)/Eu(II) 1 O M KI (6) Eu(III)/Eu(II) 1 O M KSCN ( 7 ) Eui 111)/EulII) 1 O M HClOd ~, (8j Zn(II)jin 0 10M KCl. (9) Zn(II)/Zn 1 .O M KC1 (10) Zn(II)/Zn, 1 .Ofif KKOg (11) Bi(III)/Bi 1 . O M HNOa (12) Bi(III)/Bi 1 .O M HC104 (13) Bi(III)/Bi 0.5M H2SO4 (14) CdiII)/Cd 1.OM KSO,
(17) Ti(IV)/Ti(III) (18) Ti(II:)/T1(111) (19) Ti(I1 )/Ti(III) (20) Ti(I\.)/Ti( 111) (21) Ti(I\’)/Ti(III) (22) Ti(TT‘)/Ti(III) ( 2 3 ) Ti(IlT)/Ti(I1I)
+ ne G R
Observation of Hg column height dependence AmpliPhase tude angle so so S n ~.
No
No
No So
Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
~~
Yes (small) Yes Yes Yes
... ...
Yes Yes (small So
Yes
So
Yes
Yes
Yes (small Yes
20M H2C2Q4 20.21 HzC204
Yes Yes Yes
Yes Yes
HgC204
Yes
No
+
+ 30M K2S04 + 00 40,W K2S04 20M + 0 10M SH4C1 203f HiC204 + 1 O M SH4Cl 205f HlC204 + 0 O l O i z l KC103 20M H2C204 + 0 040M KClO3
Yes
No
No
Yes
Yes
VOL. 3 6 , NO. 1 1 , OCTOBER 1 9 6 4
... . .
2219
6: + neY a t higher concentrations of sulfate ion. The behavior of the cadmium system may result from adsorption ( 2 ) . Some of the foregoing interpretations are very tentative and are based on preliminary observations. I t is apparent that not all of our experimental results are easily interpretable. While much of the data is in accord with theory based on simple mechanisms, relatively complex kinetic schemes must be invoked to explain some of the results. -4ylward and Hayes attribute streaming a t the mercury surface to be the source of drop-time dependent wave heights for the metal ion-metal amalgam systems which they examined.
R e agree that streaming should influence the time dependence of a x . polarographic currents and may be involved in some of our system? showinc! comlilicated behavior, particularly jystems 8 to 1.2. However, we are not' preiiared to rule out the possibility that these may involve mechanisms which are more complicated than has been implied in the literature. Additional work on this subject is in progress. Full details of experimental results and theoretical considerations will be submitted a t a later date. LITERATURE CITED
(1) Breyer, B., Bauer, H. H., "Chemical Analysis," P. J. Elving and I. h l . Kolthoff, eds., 1.01. 13, Chap. 4, Interscience, Sew York, 1863. (2) Ilelahay, P., "Advances In Electrochemistry and Electrochemical Engi-
neering," P. Ilelahay and C. 1T. Tobias, eds., 1.01. 1, Chap. 5, p. 273, Interscience, Sew York, 1961. ( 3 ) Hung, H. L., Smith, 11. E., A x . 4 ~ . CHEW.36, 922 (1964). (4) Hung, H. L., Smith, L). E., unpublished work. ( 5 ) Koryta, J., Koutecky, J., Vollection C'rech. C'hem. Commm. 20, 423 (1955). (6) Xatsuda, H., Z. Elektrochem. 62, 977 11958). , \ - - -
( 7 ) Orlemann, E. F., Kern, I). 11. H., J . .4m. Chem. SOC. 75, 3058 (1953). (8),Randles, J. E. B., Somerton, I
