Subscriber access provided by University of Texas Libraries

Electroanalysis and Coulometric Analysis Allen J. Bard Anal. Chem., 1966, 38 (5), 88-98• DOI: 10.1021/ac60237a006 • Publication Date (Web): 01 May 2002 Downloaded from http://pubs.acs.org on February 19, 2009

More About This Article

The permalink http://dx.doi.org/10.1021/ac60237a006 provides access to: • Links to articles and content related to this article • Copyright permission to reproduce figures and/or text from this article

Analytical Chemistry is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 fractionating columns are few. Van approach to equilibrium. In most (3) Chem. Eng. Xews 43 (26), June 28, 1965. Sway (17) has developed a fraction packed analytical columns, condenser (4) Elliev, Y. E., Devyatykh, G. G., collector for use in vacuum fractiona- holdup is generally very slight, and Dozorov, 5‘. A., Zh. Fiz. Khim. 37,2179 tion. A piston pump ejects the collected should therefore have only a slight (1963). fractions through a relief valve into effect on rate of equilibration. (5) Ellis, S. R. AI., Porter, XI. C., Jones, K. E., Trans. Znst. Chem. Engrs. (Lon- suitable storage vessels at atmospheric Haring and Knol (7) discuss the don) 41, 212 (1963). pressure. Williams (19) has described influence of reflux ratio on the separating (6) Fair, J. R., Ind. Eng. Chem. 56 (lo), an all-glass fraction cutter with a self- effect in a fractionating column. They October 1964. lubricated valve. This unit is suitable distinguish between separating per- (7).. Haring, H. G., Knol, H. W., Rec. Trav. formance as functioning at partial Chim. 83; 645 (1964). for vacuum operation at temperatures (8) Haughton, C. O., Brit. Chem. Eng. 10, as high as 300’ C. reflux and separating power as function- 237 (1965). Little has been added during the past ing under total reflux. Elliev et al. (4) (9) -James, A. T., Martin, A. J. P., Analyst two years to the fund of knowledge deal- developed equations to establish a 77, 915 (1952). (10) &fair,B. J.,Willingham, C. B., J. Res ing with analytical distillation; not similar relationship. Xatl. Bur. Std. 22, 519 (1939). only has distillation equipment been of Finally, a somewhat optimistic role (11) Martin, A. J. P., Synge, L. M., Bao- minor interest, but operating proce- is predicted for distillation by Wilcox chem. J. (London)35, 1358 (1941). dures and improved techniques have (18). He devised special equations to (12) Morton, F., King, P. J., McLaughlin, A., Trans. Inst. Chem. Engrs. (London) been scarcely considered. Pichler and establish conditions for preparing ultra- 42 (8) T-285-T-295, T-296-T-304, NO. Fetterer (13) have confirmed earlier pure materials. These equations are 182 (1964). findings on the consonance between simpler than those for the usual batch (13) Pichler, H., Fetterer, E., Erdoel continuous and intermittent with- distillation, since the quantity of the Kohle 17, 97 (1964). drawal of distillate from a fractionating second component is assumed to be (14) Romani, J. M., Genie Chim. 90, 29 (1963’l\____ column. very small. This approach may be (15) Tiong, Sie Sevan, Waterman, H. I., Barker, Jenson, and Rustin (1) devel- helpful also for the ultimate recovery in Znsenieur (Utrecht) 72. Ch. 71-82 oped equations for predicting the rate of purest form of compounds separated by (1960). (16) Sperando, A., Richard, M., Huber, approach to equilibrium of a batch dis- preparative GLC where some con- M., Chem. Zngr.-Tech. 37, 322 (1965). tillation column. The equations were tamination by eluted fixed phase from (17) Van Sway, &I., Rev. Sci. Znst?. 35, solved by an analog computer. .4c- the GLC column has occurred. 164 (1964). curacy of the equations was tested with (18) Wilcox, W. R., Ind. Eng. Chem. 3, a methylcyclohexane-toluene test mix- LITERATURE CITED Fundamentals 81 (1964). ture in a 4.5-inch diameter bubble tray (19) Williams, F. E., “Techniques of (1) Barker, P. E., Jenson, V. G., Rustin, A., Organic Chemistry,” Vol. IV, 2nd ed., column. For the column studied, J. Znst. Petrol. 49 (478), 316-27 (1963). Wiley, New York (1965). condenser holdup was the most (2) Chanda, SI., Ghosh, K. K., Chem. Age (20) Ziolkowski, Z., Filip, S., Kawaha, important variable affecting the rate of (India)14, 517 (1963). Z., Przemysl Chem. 42, 512 (1963).

Electroanalysis and Coulometric Analysis Allen 1. Bard, Department of Chemistry, The University of Texas, Austin, Texas 7871 2

HIS PAPER surveys the literature Table 7 gives the supporting electrolytes detection technique, so valuable in Tand developments during 1964 and for many coulometric . coulometric titrations. An English through December 1965, although The new edition of “Polarographic translation of the book of Abresch papers published before 1964 which have Techniques” by Meites (179) contains and Claassen on ‘[Coulometric Analysis” not appeared in previous reviews in this sections on controlled potential (1) has appeared, as well as a new book series have also been included. and and coulo- on this subject by Patriarche (207). metric titrations. The description of the Several review articles on electro- BOOKS AND REVIEW ARTICLES techniques involved in controlled analysis have been published. Szabad- A number of books dealing with potential electrolysis measurements and vary’s (264) paper gives brief biog- electroanalytical chemistry and electro- the discussion of perturbing effects in raphies for many of the pioneers and chemistry have appeared since the last coulometry are of special interest. An research workers in the field of electro- review. Volume 2a of “Comprehensive introductory book on electroanalytical analysis. Foreign language reviews of ” (296) deals with methods has also appeared (161). electroanalysis (191, 198) (Japanese), electrical methods and contains one Other books dealing with electro- electrogravimetric analysis ($1) chapter on an introduction to electro- chemistry which may be of interest to (Dutch), coulometric analysis (5, 182) chemical analysis and another on workers in the field include “The Ency- (Russian), and controlled potential electrodeposition by A. J. Lindsey. clopedia of ” (105), coulometry (257) (French) have also Purdy’s book, “Electroanalytical Conway’s “ Processes” (53), appeared. Methods in Biochemistry” (218) con- Delahay’s “Double Layer and Electrode , NEW TECHNIQUES tains an elementary discussion of con- Kinetics” (62), and Zuman’s “Organic trolled potential coulometry and coulo- Polarographic Analysis” (SIO), which Flow Electrolytic Methods. In- metric titrations, as well as other electro- discuss the fundamental principles and terest has been revived in techniques analytical methods; Table 6 in this electrode reactions which form the based on electrolysis of flowing streams book lists a number of coulometric basis of electroanalytical techniques. of solutions for analysis or separa- titrations that have been performed, the The recent book, “hperometric tions. Sporadic reports in the past limits of concentration for the deter- Titrations,” by Stock (259) contains have been concerned with attempts at minations, and their accuracy; and numerous examples of this end point carrying out the electrolysis of a flowing

88 R ANALYTICAL CHEMISTRY solution on an electrode contained in a in the flowing solution can then be cal- showed that O2 can be separated from column-a marriage of chromatographic culated by equating the current, i, air and other gas mixtures using cata- and electrodeposition techniques- with the rate of flow of solution into the lytic porous oxygen and the but recent interest in this method, de- column, G, yielding electrolytes and membranes usually scribed as electrolytic chromatography employed in fuel cells. (84,85), potentiostatic chromatography c=-i Thin Layer Electrolysis. Anson (228),or partition chromatography by nFG and co-workers (46, 47, 113, 114) intro- electrodeposition (24, 25) , may signal a duced the technique of electrolyses more widespread application of the where n is the number of electrons trans- carried out in thin layers (0.02 to 0.1 technique. ferred in the electrode reaction and F is mm.) of solution. Christensen and An- For an electrodeposition on a the faraday. son (46) showed that for electrolysis at electrode, the ratio of the concentration Eckfeldt and Shaffer (75) used this a constant current, i, at an electrode of of nietal in the mercury, C,, and in the technique to determine oxygen (and area A, and a cell thickness, I, the solution, Cm+n, is governed by the suggested the term “constant potential following equation holds : usual type of partition or distribution derivative coulometry” for the method), (Equation 1) : nFAlCO l2 employing a flow cell with silver spheres r=--- (3) as the . The obvious i 30 _-C, -D=- advantage of this method of analysis C, +n compared to galvanic analyzers with for l2 < TO, where D is the diffusion smaller electrodes is that calibration is coefficient of electroactive species, Co is unnecessary (no unknown calibration its concentration, and T is the transition terms appear in Equation 2) and the time. Under conditions where the term except that the distribution coeffi- current is independent of changes in P/3D is negligible, Equation 3 becomes cient, D, is a function of potential, temperature, electrode surface, solution Q = nFA1C” and, if electrochemical equilibrium is viscosity, etc. Oxygen at the 1-p.p.m. (4) attained, can be calculated by the level was determined by this technique the usual coulometric analysis equatioii, , as shown in Equation with a relative error within 1%; at the which holds for both constant current 1. For depositions on a solid electrode, 0.01-p.p.m. level, the error was - 10%. or constant potential analysis. The a similar equation usually holds in Shropshire (245) used a fritted glass advantage of this technique, as with which C, may be taken as 1 for amounts sparger coated with silver or platinum other electrolytic techniques involving of C, greater than a monolayer. black as the electrode in the flow cell, large electrode area-solution volume Usually D can be made sufficiently and showed that satisfactory results ratios-e.g. , flow electrolysis and high large by adjustment of the potential could be obtained for the reduction of speed coulometry-is rapid analysis that a successful separation can be permanganate ion in 3.7iV HzS04. with calculations based only on Fara- made with a single batch operation. Sovak (195) proposed an analysis of SOz day’s law. Although the early electrodes For separation of substances with at low concentrations in gas streams used in thin layer methods, accidentally similar formal potentials (E0”s), a based on the reaction of the SO2 with a or purposefully imperfect platinum-in- multiple extraction or column technique solution stream of H2S04 or Zr’azS04 con- glass seals, were rather inconvenient to may prove useful, although shifts in taining excess Iz. The I- produced as a use, improved electrodes (123, BOO) potentials by complexation or pH result of the reaction is oxidized at a make the method easier to apply. Re- variation can also be used. Other ad- platinum anode at a constant potential cently, Reilley and co-workers have vantages of a column technique include with 100% current efficiency; the presented a cell design for use with a the possibility of selective stripping of current for this oxidation is a measure of mercury-coated platinum electrode (200) deposited metals from the column, SOz concentration as given in Equation and discussed the coulometric deter- the concentration of trace quantities of 2. An internal electrolysis technique, mination of a mixture of Cu(II), Pb- metal ions, and the continuous purifica- employing a platinum-K2Cr207 cathode, (II), Cd(II), and Zn(1I) and a mixture of tion of electrolyte solutions. Tech- was used to maintain the anode C1-, Br-, and I- at a concentration level niques and cells for carrying out the potential constant. Although this of 5 to lOmX (199). The average errors process vary. Blade1 and Strohl (24, method is reminiscent of continuous in these determinations was rather large 25) and Roe (228) attempted to minimize coulometric with an electro- (about loo/,), mainly because of dif- the iR drop through the column to generated titrant, it is different in that ficulty in obtaining an accurately known obtain a uniform potential. Fujinaga it is a controlled potential, rather than a 1 and the large background current due and co-workers (84, 85) purposely intro- controlled current, technique, and does to diffusion to the edges at the electrode. duced an iR drop so that a graded poten- not require separate indicator electrodes The technique has also been used to tial down the column was established. nor the usual feedback loop for con- study adsorption of electroactive eub- Packing materials for the columns trolling the current. On the other hand, stances (114) and the kinetics of solution have included graphite (24, amalga- reagent must be added to the sample reactions of electrogenerated substances mated nickel (228) or platinum (25),and stream and the flow conditions and (47). silver (86) powders or wires. Successful conversion efficiency may be more separations of Cu, Pb, Cd, and Zn (24) stringent. Novak suggests the name ELECTROSEPARATIONS and Cu, Pb, and Cd (84, 85) have been potentiostatic coulometric analysis for reported. Under some conditions, opera- the method. Electrolytic Sample Dissolution and tion as a true chromatographic tech- Interest in fuel cell technology had led Preparation Methods. Several recent nique with the measurement of retention to application of these methods to reports have appeared on anodization times and elution curves can be ac- analysis. For example, Hz in inert gas of metallic samples as a method of complished (25). mixtures can be determined by measur- dissolution and separation. Barabas When the electrode reactions during ing the current resulting from its oxida- and Lea (10) used anodic dissolution of a the flow through the column proceed tion under fuel cell-type conditions at a Cu sample at a high current for a short with 100% current efficiency and with porous graphite-platinum black time in an automated colorimetric 1007~ conversion, coulometric mea- electrode (18). The accuracy for 0.1 to analysis of P in Cu. Anodic dissolution surements are possible. The concentra- 100% Hz is better than 10.27& techniques have also been reported for tion of the electroactive substance, C, Similarly, Langer and Haldeman (158) the analysis of oxide inclusions in

VOL. 38, NO. 5, APRIL 1966 a 89 R steel (44). The steel sample, con- tion before analysis have been described. preparation before neutron activation nected as an anode, is dissolved into an Dobahaeva (66) employed electrolytic analysis. The use of pyrolytic graphite ammonium citrate electrolyte at a deposition of Au on a C anode as a as an electrode material is of importance current density of 100 ma. for several means of concentrating the Au (present in this application because it is available hours. A residue of the oxides and at a 0.03 gram per ton level) before in a highly pure state, has a low neutron other impurities collects in the cell and spectrographic analysis. Deposition of cross section, and gives a low back- is separated and analyzed by a bromina- Au on a Cu disk electrode prior to x-ray ground count. The method combines tion procedure. spectrographic analysis has also been the selectivity of controlled potential The determination of beryllides in a described (183). procedures with the sensitivity of neu- steel sample following anodic dissolution Mark and Berlandi (270) found that tron activation analysis; determinations into a NHdF-citric acid-HC1 electrolyte controlled potential electrodeposition of Ag in concentrations as small as lO-7M has also been reported (306). Several of metals on a pyrolytic graphite have been accomplished. Deposition electrolytic methods of sample prepara- electrode is a useful method of sample of Au, Ag, Cu, and Co on a pyrolytic graphite electrode under carefully con- trolled conditions has also been shown to be useful in the preparation of standards (289). Table I. Electroseparations Dryburgh (68) described a cell for Separation preparation of sample of radioactive of From Method samples by small scale electrodeposition; As, Sb Fission Formation of AsH3 and SbH3 by flash elec- the preparation of a 14.4-k.e.v. y-ray products trolysis source of cobalt-57 was given. The As Formation of AsH3 at Pt electrode Bi co Electrodeposition of Bi at Hg cathode separation and determination of tan- Bi Pb, Fe, Cd, Selective oxidation of mixed metal amal- talum-182 and niobium-95 by electro- In, Ga, Zn gams lytic procedures have been investigated Bi, Cu Pb Electrodeposition of Cu and Bi at Pt elec- trode (100). Parker and Baumgartner (205) Bi, Cu Ni Electrodeposition at Pt electrode using in- describe a method of preparation of ternal electrolysis with Pb anode samples for electron microscopy based on Cd Ni Electrodeposition of Cd in media containing electrolysis on a specimen support grid various complexing agents covered with a thin layer of mercury. Cd, Cu, As In Electrodeposition of Cd, Cu, and As prior to polarographic determination of In After electrolysis the mercury is re- CU As Electrodeposition of Cu, followed by dep- moved and the deposited material on osition of As and evolution of AsH3 by the specimen grid is ready for observa- controlled potential tion. CU As, Cd, In, Zn Electrodeposition of Cu Cu, Zn, Ag Deposition of Pt electrode using internal Electrophoretic Deposition. Dep- electrolysis with Cu, Zn, or iclg anode osition of charged particles moving Eu Fission Reduction with electrolytically prepared as a result of an applied electric field products Li amalgam has been used for sample preparation In Fe, Zn Electrodeposition of In at controlled po- tential in radioactivity measurements in sev- In Ga, Ge Electrodeposition of In at controlled po- eral recent papers and in the past.

tential ~ Donnan and Dukes (67) deposited Mo, Ni Electrodeposition at Pt electrode as MonOa.- microgram quantities of Pu, Xp, Am, H20and Ni and Cm, employing U as a carrier and Mo, Re Electrodeposition as M0203 .zH2O and Re Ni Fe, Pb, Zn, Oxidative internal electrolvsis with PbOn, an NH4C1-NH3 electrolyte and Pt Cr, Cu Pb cathode electrode. The mode of deposition Ni Th Electrolytic reduction of Ni involves hydrous oxide formation in the Ni Electrodeposition of Ni under various con- ditions higher pH region near the cathode, Pb Sn Electrodeposition on Cu-clad Pb or Pt followed by deposition. Essentially microelectrodes quantitative recovery of the actinides is Pb co Electrodeposition of Pb at Hg cathode obtained in the presence of the carrier. Pb U Electrodeposition of Pb at solid cathode Use of a carrier was also recom- Pm Lanthanons Reduction at Li amalgam cathode in citrate U medium mended by Smith and Barnett (251) in Rh Ir Electrodeposition of Rh under various con- the deposition of Pa at a stainless steel ditions cathode employing a fluoride or oxalate Se Cu, other Electrodeposition of Se and Cu; dissoln. of medium. Deposition of Pa on a plati- metals Cu in dilute "03 Sm Pr, Nd Reduction of Hg cathode in tartrate medium num cathode from a formate medium Sn W ElectrodeDosition of Sn in oxalic acid has also been described (241). Other mediuk studies of this type include the deposi- Sn Ge Electr?d,eposition of Sn at controlled po- tion of Th, U, rare-earth elements tentiai W Tic Anodic oxidation of W in sample in NaOH (174) (under the title of molecular plating) medium @OS), and Ac (116). The general Yb Y, Er Deposition at Hg electrode from acetate- (261) theory and mechanism of electrophoretic citrate medium deposition, particularly with metal Stepwise Deposition of Metals by Controlled Potential Electrolysis powders and other inorganic suspensions, Au, Cd, Cu, Pt electrode in oxalate medium (273) have been reviewed recently by Brown Hg,Pd, Pd, and Salt (32). Electrodeposition of Sb, Se, Sn As, Cr, Fe, Pt electrode in various media (674) organic substances, which has been Mn, Pd, Se, widely used as a technological method of TP forming organic coatings [see for Si,-&, Pb Ge, Th Various media (40) example (941, may be of interest in the Cu, Cd, Co, Cu or Pt electrodes (43) Ni. Zn future as an analytical separation technique.

90 R ANALYTICAL CHEMISTRY Other Separations. Electrochem- ~~~~~~~ ~ ~ ~~ ~ ical methods for concentrating trace Table II. Electrogravimetric Determinations elements by electrolysis in the analysis Deter- of metal samples have been reviewed mination (9.2, 145, 150). Collh (51, 52) studied of Method Reference the electrolytic separation of Li isotopes Ag Controlled potential deposition in O.lN "08 and ammoni- (268, 28s) at a streaming mercury electrode in acal EDTA media LiCl and LiOH solutions. The oxida- Au Controlled potential deposition in oxalate and KaOH media Cd Controlled potential deposition in oxalate and NaOH media tion of cobalt(I1) in the presence of Efff,e,t of solution conditions on structure of electrodeposited EDTA using an internal electrolytic bU technique with a PbOz cathode prior Rapid eledtrodeposition on Winkler electrodes (125) to the photometric determination of Co cu Deposition at controlled potential (60, ' 98, 268, 278) has been investigated (154). Fong (81) Deposition at vibrating and Winkler electrodes (79, 125) has studied the electrolysis of rare earth Constant current depositions; determination in A1 alloys, (17, 110, 284) ions in CaFz, SrCl2, and BaBrl in the copper naphthenate, and other solid state at temperatures of Internal electrolysis, using Zn anode 300- co Cathodic deposition from various complexing media 700' C., at W or Au electrodes. Al- Deposition at rotating Pt cathode; interference of various though the purpose of this work was not ions studied analytical, the concept of solid state Fe Deposition at controlled potential in oxalate and NaOH electrolysis is an interesting one, partic- media Hg Deposition at controlled potential in oxalate and NaOH ularly in light of recent interest in solid media state reactions in analytical chemistry In Deposition at Cu-clad Pt cathode at controlled potential in (291). Table I summarizes other work oxalate-HC1 medium in electroseparations. MO Deposition as hIoz0~.3Hz0at controlled potential at Ni- plated electrode Ni Cathodic deposition from various complexing media Pb Deposition as PbOz at Pt anode Depositions as Pb Further developments in the use of Pd Controlled potential deposition of Pd in various media electrodeposition methods involving ra- Pt Constant current deposition at Pt electrode dioactive tracers for measuring rates of Sn Controlled potential electrodeposition at Cu-clad Pt elec- exchange reactions have been reported trode from various oxalate media (26). Carman and LMarkham (42) de- Rapid deposition on Winkler electrodes scribed the electrodeposition of Pb Te Controlled potential deposition from various media U Deposition at UOz.2H20 on Pt electrode by internal elec- as PbOz on a Pt electrode; the electrode trolysis using Cd or Zn anode and deposit were immersed in distilled Zn Controlled potential deposition in oxalate and NaOH media water during the final weighing. This Deposition by internal electrolysis using A1 anode technique has the advantage of not re- quiring drying the electrode, and yet does not necessitate measuring the density of the deposition medium. in series with an identical cell containing appreciable solvent reduction or oxida- Even with the necessary buoyancy the sample at a slightly higher con- tion occurs. corrections, an average error of only centration. Controlled potential cou- Goode and Herrington (96) used a *0.2 mg. for 40-mg. quantities of Pb lometry is carried out in the standard modification of the previously reviewed was reported. This method seems until the current decays to background, high-speed coulometry technique, in- particularly attractive for deposits and then in the sample cell, integrating volving a cell with a large electrode which might undergo unknown changes the current for the remainder of the area-solution volume ratio, and carried on heating. Rosanda (250) observed electrolysis in the usual way. The out the electrolytic reduction of Fe(II1) that occlusions of organic material amount of electroactive substance in the and oxidation of Pu(II1) with electroly- which sometimes occur during the sample is equal to that in the standard sis times less than two minutes. Johans- electrodeposition of Cu by a constant plus the amount determined by the son (121) also described an efficient current method do not occur when de- additional electrolysis. The major electrolysis cell composed of rotating position is carried out by a controlled advantage of this technique appears to platinum gauze disks in a small solution potential method. Other work on be an automatic cancellation of the volume, and used it to monitor the electrogravimetric methods is sum- residual current during the major part of effluent of chromatographic columns. marized in Table 11. the electrolysis, if it is assumed that the At flow rates below 1 ml. per minute, standard and sample cell conditions are less than 0.5y0of the effluent material- almost identical. Errors below 0.1% in e.g., copper ion-was unreduced. CONTROLLED POTENTIAL COULOMETRY the determination of 0.4-mg. amounts Takata and Muto (270) also used a of Cr were obtained when similar coulometric cell containing a Cu gauze Determinations. The latest value amounts of standard and sample were electrode for monitoring the effluent of of the faraday is 96,487.0 coulombs employed. King and Bard (133) a cation exchange chromatographic per equivalent based on a carbon-12 pointed out the advantages of measuring column. The separation, detection, and scale and an atomic weight of silver the amounts of gas evolved during a estimation of .h(III), Cu(II), and Fe- 107.870 (104). Several variants of con- coulometric electrolysis. One applica- (III), were described. trolled potential coulometry have been tion of this technique is in elucidating The examination of boron carbide described. Rechnitz and Srinivasan the mechanism of electrode reactions electrodes for controlled potential cou- (2.24) described a differential coulo- and was employed in studying the lometry was reported; results of this metric technique and its application to electrochemistry of the methylhydra initial study do not appear promising the reduction of dichromate to zines (134). The method may also be (187). Modifications of the Karl chromium(II1). In this technique, a of value in making corrections for Fischer titration method for the deter- cell containing a standard amount of electrolysis of the solvent for electrode mination of water, previously used as a substance to be determined is connected reactions occurring at potentials where coulometric titration technique, for

VOL. 38, NO. 5, APRIL 1966 91 R use in controlled potential coulometry Electrode Mechanisms. Meites direction, an estimate of the rate con- have been described. In Lindbeck and (178) showed that in the coulometric stant of reactions consuming the species Freund’s method (162), the Karl Fischer electrolysis of a substance undergoing a electrogenerated during the first electrolyte, 0.15M SOz, 0.6M pyridine, totally irreversible electrode reaction, electrolysis can be made. The tech- 0.1M NaI in , is added to the complete reduction or oxidation occurs nique was checked by investigating one cell and a known quantity of iodine is at any potential where appreciable of the favorite reactions of electro- generated. The sample is added and current flows-Le., at potentials on the chemists, the hydrolysis of benzo- allowed to react, and the excess iodine is rising part of the polarographic wave; quinone imine, electrogenerated by the determined by controlled potential the reduction of hydrogen ion on mer- electrooxidation of p-aminophenol. coulometric reduction. A blank cor- cury was used to demonstrate this case. Rechnita and McClure (225) discussed rection for the amount of iodine lost in An evaluation of the rate constants for the application of controlled potential the absence of sample is necessary. various competitive and competing coulometry to the study of reactions in Water in methanol and dimethyl sul- reactions in controlled potential coulom- which the electroactive species is re- foxide in 10- to 80-pg. amounts was etry has been described (90). generated by a chemical reaction follow- determined with standard deviations of The technique of reversal coulometry ing the electrode reaction (a catalytic 0.2 to 0.3 pg. In the method of Rechnita has been introduced to study reactions reaction). When reactions like this and Srinivasan (225),all of the iodide in following the electron transfer reaction occur, a steady state current signifi- the Karl Fischer reagent is oxidized to (11). The technique involves carrying cantly higher than the background iodine, and the iodide produced as a out a coulometric reduction (or oxida- current occurs, and by a study of the result of reaction of the water was deter- tion) for a known time, followed by a variation of the steady state current mined by controlled potential oxidation. change of potential-for example, to with steady state concentrations, the Errors of 1 to 5$Z0 were reported for cause oxidation (or reduction) of the order and rate of the catalytic reaction 1- to 2-mg. amounts of water. Other electrogenerated species. From the can be determined. The reaction controlled potential coulometric deter- difference in the amount of between IrC16-2 and C103- was studied minations are summarized in Table 111. consumed in the forward and reverse using this technique (221). Controlled potential coulometry was used in the study of a number of in- organic electrode reactions. The re- Table 111. Controlled Potential Coulometric Determinations duction of Be(Hz0)4+2was shown to Substance occur in a two-electron reaction to determined Method Be(OH)z, H2, and water in a 0.5M LiCl Ag Trace amounts in U (nuclear fuel) medium (244). Ward and Wright (294) Am Reduction of Am(V1) -r Am(V) at Pt electrode in 2M showed that the oxidation of azide ion (NHq)zSO4-0.2M H2SOa produces nitrogen in a one-electron co Reduction of cobalt-60( 11) at microelectrode reaction. Desideri (65) investigated Cr Cr(V1) --t Cr(II1) at Pt electrode Cr(II1) --t Cr(I1) in fused KC1-LiCI the reduction of permanganate at cu Cu(I1) --r Cu(0) in microgram amounts using I-& various concentrations of mineral acids. recorder At concentrations of below 2M, Cu(I1) + Cu(0’l in fused KCl-LiCl~ ~ .~ the apparent number of electrons in- Eu Eu(II1) + Eu(I1) at Hg electrode or Eu(I1) -+ Eu(II1) at Pt electrode in 0.1M HC104 volved in the reaction (n) was five. Eu(II1) 4 Eu(1I) at Ha- electrode in acetonitrile At higher &So4 concentrations, n medium decreases, becoming two in 18M H2804. Fe Fe(II1) --t Fe(I1) at Pt electrode The reduction of titanium tetrachloride Ni Ni(I1) -r Ni( 1V)-dimethylglyoxime complex at Pt electrode in acetonitrile was shown by Kolthoff Pb Pb(I1) 4Pb in microgram amounts and Thomas (142) to occur in two one- Pd Pd(I1) -f Pd(0) at Au or Hg electrode electron steps to Ti(II1) and Ti(11). Pt Pt(I1) 4 Pt(0) in fused KCI-LiC1 Jones and Anson (194) used coulom- Pu Pu(II1) + Pu(1V) at Pt electrode Rh Rh(II1) + Rh(0) at Hg electrode etry to study ligand bridging by Sm Sm(II1) -,Sm(I1) at Hg electrode in acetonitrile chloride and iodide ion in the oxidation Sn Sn.ama1ga.m --t Sn(II), following reduction of Sn( IV) of Cr(1I) at a mercury electrode. The in bromide medium U Review of methods reduction of Mo(V1) in acidic chloride U( VI) 4 U( IV) in presence of various metals media was studied by Wittick and Rechnita ($01). Israel and Meites V V( 111) + V( IV) in fused KCl-LiC1 (116) studied the oxidation and reduc- Reductions and oxidations of various V species in 1M tion of various vanadium species a HzSOr3M KHSOd at Trace amounts of U (nuclear fuel) mercury electrode in sulfate media and described several possible analytical Organic Substances applications of the electrode reactions. Substituted Oxidation (n = 2) at Pt electrode in 1M His01 h droquinones The reduction of Re(VI1) in H2S04was p-Plenet idine Oxidation (n = 2) at Pt electrode in 1M HzSOd shown to occur by a three-electron re- N-Substituted Oxidation (2e) to sulfoxide; oxidation (le) to radical action when the reduction was carried phenothiazines at Pt electrode; or reduction (2e) of sulfoxide at Hg out under the usual electrolytic condi- electrode Azo-dyes Reduction at Hg electrode tions (2446). When the electrolysis is carried out under high speed electrolytic Others conditions, however, n values of about Fluoride ion Controlled potential generation of Ce( IV) in null point potentiometry 1.4 were obtained. This was ascribed to Hydrogen, in Fe Integration of current-potential curves for slow po- the reduction of Re(VI1) to the VI tential scan state, followed by a slow disproportiona- HTO Methods based on (see text) tion of the Re(V1) to the VI1 and IV Nitrate ion Catalytic reduction in presence of U(II1) as a catalyst at Hg cathode states. VanLoon and Page (288) investigated the reduction of Rh(II1) by coulometry

92 R ANALYTICAL CHEMISTRY and in a chloride medium. aqueous solution was studied by Turner (Clod)* solution and titrating with Page and Zinser (203) have reinvesti- and Elving (286); although the results electrolytically generated base. The gated the reduction of Ir(1V) in a were somewhat complicated by film water is reacted with PC15; the HCl perchlorate medium, and find results formation on the electrode, they were in produced in this reaction is reacted with different from those of Rechnitz and general agreement with previous studies NaHC03; and the COz which is pro- McClure (222). The latter authors at platinum electrode in nonaqueous duced is determined as before. The explained n values larger than one by a solvents. Gardiner and Collat (86) determination of carbon and hydrogen reaction between Ir(II1) and perchlorate demonstrated that the oxidation of in a 5-mg. picric acid sample was re- ion, leading to steady state currents borohydride ion in alkaline aqueous ported with average errors of 1.0.3 and larger than background. Page and solutions at a mercury electrode occurs *0.2%, respectively. Zinser failed to find limiting currents with n = 8. Badoz-Lambling and Stojkovic (8) larger than background and explain the The electroreduction of tetraphenyl- described a coulometric titration of high n values as some iridium being in stibonium ion at a mercury electrode in phenothiazine in an acetonitrile solution. an oxidation state higher than IV. 0.1M KC1 was shown to occur in two The oxidation of phenothiazine, P, to Coulometric methods have also been steps by Morris and eo-workers (186). the radical R, occurs first. When the used in the study of electrode reactions Reduction at the first step occurs with current efficiency of [his process drops of organic substances. Spritzer and n = 1 and yields diphenylmercury and below 100~o,the reaction which occurs co-workers (255) found that the re- triphenylstibine; for the second step, is the oxidation of R in another one- duction of pyridinium ion in a pyridine n = 2, and triphenylstibine and ben- electron step to S. Because any solution containing 0.1M LiC104 occurs zene are formed. King and Bard (134) generated S will react with P to pro- in a one-electron reaction. Struck and studied the oxidation of several methyl- duce R in the bulk solution, the overall Elving (262) investigated the behavior hydrazines at a platinum electrode in current efficiency for the process P + R of the alloxan-alloxantin-dialuric acid &SO4 solution. Methylhydrazine is remains 100%. Several different poten- system using polarography, coulometry oxidized in a four-electron reaction, tiometric and amperometric end point and product analysis; the reduction of just as hydrazine itself is; the mode detection techniques were described. alloxan in an aqeuous buffer at pH = 4 of oxidation of the dimethylhydrazines Aikens and Carlita (4)have proposed occurred with n = 2, and yielded dia- is somewhat more complicated and was the novel concept of coulometric genera- luric acid. The reduction of vitamin elucidated using gas volume and chrono- tion of a titrant from a thermodynami- B12a (aquocobalamin) at a mercury potentiometric measurements during cally unstable species and demonstrated electrode in aqueous buffers was studied the course of the coulometric oxidation. that the electrogeneration of Cr(I1) in by Hill et al. (112). At pH’s of 1 or 8 Valenta and Koryta (287) used a acidic solutions could be accomplished the reduction yields vitamin B12r X small auxiliary mercury electrode to with a high current efficiency. Because (n = 1); at pH 8 and more negative record current potential curves on an the reduction of Cr(H20)6+3occurs at potentials, vitamin B12s (n = 2) is oscilloscope during the electrolysis. about -0.65 volt us. N.H.E. and is produced. The analysis of solutions during a con- kinetically controlled, a good current Gelb and Meites (91) studied the re- trolled potential electrolysis by electro- efficiency for the generation of Cr(I1) duction of a-furildioxime using polar- chemical, spectrophotometric, or chro- cannot be obtained in strongly acidic ography and controlled potential matographic methods is a powerful tool solutions. However Cr(Hz0)5Br+2,an electrolysis. Evidence was presented in elucidating the course of a complex unstable but substitution inert coordina- for a chemical reaction following the electrode reaction. tion compound, reduces at -0.105 volt initial electrode reaction producing us. N.H.E. [an underpotential of 0.30 another electroactive species (an ECE CONTROLLED CURRENT volt relative to the thermodynamic reaction) , and an analysis of the current- COULOMETRY-COULOMETRIC TITRATIONS reduction potential of Cr(Hz0)6+3, the time curves during the controlled poten- Determinations. Eckfeldt and stable equilibrium species], so that tial electrolysis was employed to Shaffer (76) have reemphasized the pro- Cr(I1) can be generated successfully determine rate constants. Controlled posal that the coulomb be established from this species. The authors point potential electroreduction and coulom- as the standard for volumetric work. out that this general behavior can be ex- etry were employed by Brkant and These authors demonstrated that pre- pected for electrode reactions where the Merlin (29) to study the mechanism of cise results can be obtained in the titra- reactant is a thermodynamically un- reduction of 1,2-dinitrobenzene in acidic, tion of acids with commercially available stable but substitution inert coordina- aqueous solutions. Reduction at poten- equipment. Several new applications tion compound and the product of the tials corresponding to the second polaro- of the Karl Fischer coulometric titration electrode reaction is substitution labile. graphic wave was shown to yield o- have been described (21.4, 290). Two Durand and Tremillon (74) reinvesti- benzoquinone diimine (n = lo), which papers have appeared using coulometric gated the oxidation of mercury in acetic can undergo further coupling or hydroly- titrations of the combustion products of acid-acetic anhydride media and pro- sis reactions. organic substances in carbon and hydro- pose that the previously described coulo- Coulometric methods were also used gen determinations. In one method metric titrations of acetate in acetic to study the reduction of diazoaceto- (103) the organic compound is converted anhydride [for example, (175)] are phenone in aqueous buffers at various to COz and water by treatment with precipitation titrations involving the pH’s (54). Solon and Bard (252) Co304. The water is determined by precipitation of mercury(I1) acetate, showed that the stable radical diphenyl- electrolysis in an electrolytic hygrom- rather than acidimetric ones. picrylhydrazyl (DPPH) is reduced and eter (a cell for electrolyzing water Bishop and eo-workers (21, 22) dem- oxidized in acetonitrile solutions in one- composed of Rh electrodes and P206). onstrated that controlled current two- electron reactions to DPPH- and The COZ is passed through a LiOH electrode potentiometry (differential DPPH+, respectively. These authors converter where an equivalent amount electrolytic potentiometry) is a sensitive also studied the reaction of DPPH and of water is produced, which is analyzed end point detection technique in coulo- bromide ion by an analysis of coulo- as before. The standard deviations by metric titrations. The authors describe metric data based on previously re- this method were *0.30j, for carbon a microcell with a solution volume of viewed theoretical work and proposed and &0.03% for hydrogen for 2- to 10- about 0.01 ctl. for titrations of 2 X a mechanism for the reaction (253). mg. samples. 104M chloride or bromide ion in 0.01M The oxidation of tetraphenylborate In the second method (172),the CO, HNOr80% methanol (22). Both ion at a pyrolytic graphite electrode in is determined by passing it into a Ba- macro and micro amounts of acids have

VOL. 38, NO. 5, APRIL 1966 93 R been determined using this end point indicator electrode is monitored. For determining hydrogen and chlorine in detection technique with antimony slow reactions, the amperometric HCI gas streams based on fuel cell electrodes (22). A method of end point current increases continually because principles. Hersch and co-workers location based on using the generator the bromine concentration continually (109) recommend electrolytic generation electrode as a potentiometric indicator increases, while for fast reactions the of gases for the calibration of gas electrode, during periods when the amperometric current remains small un- analyzers. Methods for direct genera- current is not flowing, has also been til all of the reactant is consumed. tion of 02,Hz, D2, Nz, Clz, C02, NO, proposed (6). For intermediate reaction rates, a CZH6, 03, AsH3, and SbHs and indirect Several new applications of coulo- plateau is obtained in the ampero- production of CH4, C2H2, and H2S are metric detectors in gas chromatography metric current time curve; for reactions given. have been described. Coulson (58) giving this response the rate constant Stripping Methods. Determina- found that mercury-coated platinum can be determined by noting that at tions of the thickness of deposited was a better electrode than silver for the this steady state condition, the rate of metals, such as Ni on brass, Cd on Cu microcoulometric titration of chloride reaction = rate of bromine addition = or steel, Cu on brass, and Zn on Cu, in column effluents. Martin and Grant i/2F. brass, or steel, have been reviewed (192). (173) detected sulfur effluents by com- Continuous Coulometric Titrations. Tribalat and Mofidi (278) showed that bustion to SOzand titration with electro- Takahashi and Sakurai (266) reviewed the anodic oxidation of Re occurs with generated iodine. A titration of mercap- applications of automatic recording 100% current efficiency and suggested tans with electrogenerated silver equipment for continuous coulometric the coulometric determination of Re using an acetic acid solution has also titrations of As(II1) and Fe(I1) with films and alloys. A method for the been described (83). Among other re- bromine and permanganate and di- investigation of Ag-Cu alloys based on ported applications, Mead et d. (177) chromate ions and chlorine with Fe(I1). observation of the potential-time curve used electrogeneration of silver ion to Barendrecht (12) described a cell and during a constant current anodization study the formation of amine complexes instrumentation for a continuous Karl has been described (176). Recording of in acetone. Christian (49) found coulo- Fischer titration. Buck and Eldridge the potential-time curve was also metric titration to be a convenient (36) dsscribed the continous titration employed by Rao and Vdupa (220) in method of calibrating micropipets. The of unsymmetrical dimethylhydrazine the determination of oxygen in solid use of glass coated with tin oxide, in p.p.m. amounts with electrogenerated PbOz. “conducting glass,” as indicator bromine. Titration systems for monitor- electrodes and as generator electrodes in ing a minor constituent in a gas APPARATUS coulometry has been described (71). stream-e.g., boranes in air-based on Br6ant and Robin (SO) have included a coulometric titration (181) and for Lott (167) has reviewed instrumenta- coulometric and other electrochemical determining chlorine in gases (664) tion for coulometry and electrodeposi- methods in a training program. have been described. Other continuous tion. Applications of operational ampli- Measurements of Reaction Rates. coulometric titrations reported include fiers to electroanalytical studies have Several new applications of coulo- the determination of iron in water (232) been reviewed (118). Booman and metric titrations to the measurement and ozone (69). Holbrook (28) have discussed the design of the rate constant, IC, of homogene- A patent has been granted for a cell in of optimum stabilization networks for ous chemical reactions have been which the generator and counter elec- use in potentiostatic circuits. Although reported. These methods have the trodes are separated by ion exchange this study is primarily concerned with advantage of providing convenient resin (136). Kesler and co-workers (132, polarographic instrumentation, many addition of the reactant, particularly 296) have described the application of of the considerations-cg., optimization unstable ones such as bromine, and, coulometric titrations to determinations of rise time and effect of uncompensated being ideally suited to low concentra- in pulping liquors. resistance-apply to for tions, are capabk of use in the measure- Galvanic Analyzers. Interest re- macroscale electrolysis as well. In a ment of rapid reaction rates. Dubois mains high in galvanic oxygen an- later paper (I%), the simplified use of (69) proposed a method of continuous alyzers based on the reduction of transfer functions for cells and circuits coulometric generation of a reactant, oxygen at a silver or gold electrode, is described and applied. The papers by maintaining the concentration of the usually covered with a thin mem- Osterwald (202) and Pepersack et al. reactant at a low constant value. brane of polyethylene, Teflon, or (210) on factors affecting the behavior Using this technique, Dubois studied the polyvinyl chloride, in a cell employing of potentiostatic circuits are also of bromination of several amines, and a consumable anode, usually of lead or interest. The descriptions of two cells measured IC’s of 108 to lOQ liters/- cadmium (9, 13, 122, 165, 215, 227, 292, for controlled potential electrolysis have second. In a later study (70),the re- 303). The use of the galvanic oxygen been published (55, 608). actant (bromine) was generated with analyzer for the determination of Coulometric Titration Apparatus. a constant current and the rate of con- oxygen in gas chromatography has been Patents for two coulometric reagent- sumption of the bromine upon addition investigated (211). Applications of the generating cells have been reported of a reactant was followed ampero- water analyzers based on the electrolysis (14, 136). A transistorized stabilized metrically. of water at platinum electrodes covered constant current source has been de- Other workers using this technique with Pzo5 (the electrolytic hygrometer scribed (163). Two titrators based on included Riccoboni and Oleari (226), or Keidel cell) have been described potentiometric end point detection have who measured the rates of iodination of (209, 293). been designed. Johansson’s (120) ap- (CH&Pb, (CZHdJ‘b, and SndCzHd6 by In the determination of water in paratus is based on solid state generation of iodine, and Janata and liquid hydrocarbon streams, the water operational amplifiers and was used for Zyka (117), who determined the rate of was chromatographically separated be- acid-base titrations with automatic bromination of diphenyl sulfide. fore it passed on to the detector (209). reduction of the current in the vicinity O’Dom and Fernando (196) employed a Hibbs and Nation (111) proposed a of the end point to prevent over-titra- modification of the amperometric tech- method for the determination of p.p.m. tion. The instrument of Steed and nique to follow the course of a reaction. amounts PbO based on reduction of the Fransman (266) can be used for either In this method, bromine is generated PbO with hydrogen and determination manual or coulometric titrations. Two with a constant current in the presence of the water with a water analyzer. potentials are set on the instrument. of a reactant, and the current at the Guthke (102) developed analyzers for When the first potential is reached,

94R ANALYTICAL CHEMISTRY pulsed addition of reagent, in pulses of variable duration, occurs. The titra- Table IV. Electrogenerated Titrants and Substances Determined by Coulometric tion terminates at the second potential. Titration Apparatus for the automatic coulo- Electro- metric titration of bases in concentra- generated tions as low as 5 pg. per ml. (240) and for titrant Substance determined Reference carbon and sulfur in metals (37) have Oxidants been described. Eckfeldt and Shaffer Chlorine Methionine (77) have designed a semiautomatic Pheriplbutazonc precision pipet capable of delivering Bromine Bismith [by precipitation of BiCr(SCN)G; titration of milliliter size samples with a standard SCN-I deviation of &0.02% and said to be Anthranilic acid, Cu anthranilate ~Cu, Zn, Co, Ni, anthranilates especially suitable for use in coulometric Furan titrations. Dihydralazine Potentiostats. Brown (33) de- Phenylbutazone Cyclic 0-diketones scribed the design of a hlethionine used in the dissolution of nuclear Vinyl acetate, styrene, a-methyl styrene reactor fuel elements; an equivalent 1,3,5-Trihydroxybenzene circuit for the electrolytic cell used Dihydric phenols Tetramethyllead to test the circuit is given. In a later Tetraethyllead report (34) he suggested that a study of Iodine Total arsenic and arsenic(II1) in glasses the noise generated at a bubbling Total antimony and antimony(II1) in glasses electrode may be of use in the design of Arsenic( 111) potentiostats. Rogers (229) discussed Antimony( 111) Hydrogen peroxide (by iodometry; titration of excess a transistorized differential amplifier thiosulfate) for use as a potentiostat with an ex- H.S tremely wide output current range (1 2,31Dimercaptopropanol pa. to 10 ) at up to 20 volts Xanthates 1,3,5Trihvdroxvbenzene with a response time of 1 msec. and a Hypobromite Aminooxi- group maximum input current of 3 nanoa. X Iron( 111) Titanium( 111) solid state potentiostat based on a Platinum( 11) Titanium(I1) in LiC1-KCl melt silicon-controlled rectifier and a Reductants unijunction transistor circuit have been Iron(11) Chlorine described by Lindstrom and Davis Vanadium( V) (163); the instrument can supply up to Iridiumi 1x7) Titanium(111) UraniuA(V1) 5 amperes and 10 volts, with a response Molybdenum( VI) time of 40 nisec. Potentiostats for Phosphate [by precipitation of molybdate, titration of (165) continuous and discontinuous electroly- molybdenum( VI)] sis have been described (78). Tin(I1) Selenium( IV) ($80,$81) Copper(I) Iridium(IV) ’ (257) Of particular interest to Russian Vandium( 111) Iron(III), vanadium(V), chromium(VI), manganese(S’I1) (279) electrochemists are the potentiostat of Molybdenum( V) Chromium( VI) (80) Pamfilov and Skakun (204), designed Chromium( 11) p-Sitrophenol, p-nitroaniline, nitrobenzoic acids (4) primarily for kinetic investigations, Precipitating and Complexing Agents that of Marshakov and Zakutskii (171), Silver( I) Methyl bromide (converted to bromide ion) based on a servo-mechanism device, and Halides, cyanide in LiNO,-KNO3 melt one (166)based on operational amplifier- Halides in T\TaN03-KN03 melt Halides type circuitry with a high input imped- EGTAa Calcium( 11) ance (3.3 X lo8 ohms) and a maximum Ferrocyanide Cadmium( 11) output current of 50 ma. and 100 volts. Cyanide Nickel( 11) Two descriptions of the Tacussel poten- Acids and Bases tiostat have been given (189, 265). Base Organic acids in benzenemethanol or l-butanol-meth- (67) Wood (302) described an all-transis- anol torized potentiostat with an output of Organic acids in isopropanol media (119) 1 and 50 volts and with pro- Organic acids in acetone ( 260 Boron (converted to boric acid) (184, 306) vision for automatic scanning of poten- C02in gases (5’09) tial. Oxide ion Zinc(II), cadmium(I1) in KN03-NaN03 melt (26) In addition to the many commercial Ethylene glycol bis(0-aminoethyl ether)-N,N‘-tetraacetic acid. potentiostats now available, a number of commercial highly regulated power supplies employ feedback circuitry which can be converted with little difficulty to potentiostatic operation. ACKNOWLEDGMENT (3) Agasyan, P. K., Zh. Vses. Khim. Obshchestva im. D. I. Mendeleeva 9, 167 IlrIfiAl For example, Birman (20) discusses The author is indebted to Nartha \Ad”=,. modification of a modern program- Weaks and Beverly Keegan for their aid (4) Aikens, D. A., Carlita, &I., ANAL. mable power supply to this applica- in preparation of this manuscript. CHEM.37, 459 (1965). tion. (5) Alexander, W. A., Barclay, D. J., McMillan, A., Analyst 90, 504 (1965). The use of an integrator circuit in- LITERATURE CITED (6) Babko, A. K., Pilipenko, A. T., Rozen- corporating a French operational ampli- (1) Abresch, K., Claassen, I., “Cou- fel d, A. L., Zavodsk. Lab. 30, 1060 fier in coulometry has been proposed lometric Analysis,” Chapman and Hall, (1964). (108). A microcoulometer based on London, 1964. (7)Baboian, R., Hill, D. L., Bailey, (2) Achiwa, S., Hinatsu, E., Shigakenritsu R.A,, Can. J. Chern. 43, 197 (1965). radioactivity measurements of deposits Tanki Daigaku Gakujutsu Zasshi No. (8) Badoz-Lambling, J., Stojkovic, D., of silver-1 10 has been described (38). 2, 5 (1961). Bull. SOC.Chim. France 1963, p. 176.

VOL. 38, NO. 5, APRIL 1966 95 R (9) Baker, W. J., Harvey, F. H., Delaune, (50) Christian, G. D., Knoblock, E. C., (90) Gelb, R. I., Meites, L., J. Phys. S. D., ISA Proc. Symp. Instr. Methods Purdy, W. C., ANAL.CHEM. 37, 292 Chem. 68, 630 (1964). Anal. 7, 47 (1961). (1965). (91) Ibid., p. 2599. (10) Barabas, S., Lea, S. G., AXAL.CHEM. (51) CollBn, B., Acta Chem. Scand. 17, (92) Gladyshev, V. P., Synkova, D. P., 37, 1132 (1965). 2410 (1963). Enikeev, R. Sh., Kucherenko, N. A,, (11) Bard, A. J., Tatwawadi, S. T., J. (52) Ibid., 18, 805 (1964). Voilokova, I-.V., Tr. Komis. PO Analit. Phys. Chem. 68, 2676 (1964). (53) Conway, B. E., “Electrode Proc- Khim., Akad. Nauk SSSR, Inst. Geo- (12) Barendrecht, E., U. S. Patent esses,” Ronald, New York, 1965. khim. i Analit. Khim. 15, 213 (1965). 3,131,133 (April 28, 1964). (54) Coombs, D. RI., Leveson, L. L., (93) Gladyshev, V. P., Tember, G. A., (13) Bazzan, T., Bordonali, C., Comit. Anal. Chim. A4cta30, 209 (1964). Geinrikhs, K. Ya., Kozlovskii, 31. T. Sad. Eneraia Nucl. RT/CHI-17, 9 (55) Costa, J. M., Spritzer, &I. S., Zh. Prikl. Khim. 37, 2606 (1964). pp. (1964). Elving, P. J., ANAL. CHEM.36, 698 (94) Gloyer, S. W., Hart, D. P., Cutforth,

114) Beckman Instruments. Inc.. Brit. (1964).\-- - ~ R. E., O$lc. Dig. J. Paint Technol. Eng. ‘ Patent 972,172 (October 7, 1964). (56) Costanzo, D. A., Ibid., p. 2042. 37, 113 (1965). (15) Bernal, E., Pino, F., Injorm. Quim. (57) Cotman, C., Shreiner, W., Hickey, (95) Goncharova, K. I., Kovalenko, P. Anal. 17, 130 (1963). J., Williams, T., Talanta 12, 17 (1965). N., Bogdasarov, K. K., Zh. Analit. (16) Beronius, P., 2. Physik. Chem. 158) Coulson. D. M.,SRI Pesticide Res. Khim. 19, 671 (1964). (Frankfurt) 42, 45 (1964). Bull. 2. 9 (1962’). (96) Goode, G. C., Herrington, J., Anal. (17) Bertoldi, S., Tartari, A., Alluminio (59) Damaschke, ’K., Luebke, RI., Chem- Chim. Acta 33, 413 (1965). 31, 127 (1962). iker-Ztg. 88, 547 (1964). (97) Goode, G. C., Herrington, J., Hall, (18) Bianchi, G., Faita, G., Mussini, (60) Danh, T. T., Viguie, J. C., Anal. G., Ibid., 30, 109 (1964). T., J. Sci. Instr. 42, 693 (1965). Chzm. Acta 33, 532 (1265). (98) Gorbatova, G. A., Materialy 4-oi (19) Binder, E., Goldstein, G., Lagrange, (61) Davis, D. G., Boudreaux, E. A., J. [Chetvertoi] iyauchr. Konf. Asparantov P., Schwing, J., Bull. Soc. Chim. France Electroanal. Chem. 8, 434 (1964). (Rostov-on-Don, Rostovsk. Unav.) Sb. 1965, p. 2807. (62) Delahay, P., “Double Layer and 1962, p. 137. (20) Birman, P., “Power Supply Hand- Electrode Kinetics,” Interscience, New (99) Graciani, E., Bernal, E., Pino, F., book,” p. 129, Kepco, Inc., Flushing, York, 1965. Inform. Quim. Anal. (Madrid) 19, 45 N. Y., 1965. (63) Delgado, 0. A., Rev. Fac. Ing. Quzm. (1965). (21) Bishop, E., Dhaneshwar, R. G., L’nzv. >Iracl. Litoral, Santa Fe, Arg. (100) Grandjean, Ph., Lerch, P., Monnier, ANAL.CHEM. 36, 726 (1964). 31, 75 (1962). R., Helv. Chim. Acta 43, 848 (1960). (22) Bishop, E., Short, G. D., Analyst (64) Ibid., 32, 115 (1963). (101) Gurvich, D. B., Balandina, 5’. A., 89, 587 (1964). (65) Desideri, P. G., J. Electroanal. Chem. Paikina, L. M.,Zavodsk. Lab. 30, 278 (23) Biswas, S. D., Dey, A. K., J. Prakt. 6, 344 (1963). (1964). Chem. 21, 147 (1963). (66) Dobzhaeva, E. D., Materzaly po (102) Guthke, H., Chem.-Ingr.-Tech. 37, (24) Blaedel, W. J., Strohl, J. H., AKAL. Geol. i Polezn. Iskop. Buryalsk. ASSR, 587 (1965). CHEM.36, 1245 (1964). Buryatsk. Geol. Upr. Suppl. No. 6, 03) Haber, H. S., Bude, D. A., Buck, 37, (25) Ibid., 64 (1965). 17 (1961\.\-- -~ R. P., Gardiner. K. W.-ANAL. CHEY. (26) Bombi, G. G., Fiorani, AI., Talanta (67) Donnan, RI. Y., Dukes, E. K., ANAL. 37, 116 (1965). ’ 12, 1053 (1965). CHEM.36, 392 (1964). 04) Hamer, W. J., Craig, D. N., J. (27) Bombi, G. G., Fiorani, M.,Mazzoc- (68) Dryburgh, P. >I., J. Sei. Instr. 41, Electrochem. SOC.11 1, 1434 (1964). chin, G., J. Electroanal. Chem. 9, 457 640 (1964). 05) Hampel, C. A., “The Encyclopedia (1965). (693 Dubois. J. E.. Z. Elektrochem. 64. 143 of Electrochemistry,” Reinhold, New (28) Booman, G. L., Holbrook, W. B., . (1960). ‘ York, 1964. ANAL.CHEM. 37. 795 (1965). (70) Dubois, J. E., Alcaia, P Barbier, 06) Hanamura, S., Nagoya Kogyo hpIerlin, J.,’ Bull. SOC. G., J. Electroanal. Chem. 8, 359 (1964). Gijutsu Shikensho Hokoku 11, 464 e 1964, g. 53. (71) Dubrovinskii, V. Ya., Kumok, V. (1962’). d., Robin, J., Chim. Anal. N., Zh. Analit. Khim. 19, 1159 (1964). Hargis, L. G., Boltz, D. F., Talanta (72) Dumas, T., Latimer, R. A., J. Agr. 11, !57 (1964). Food Chem. 10, 276 (1962). (108) Henin, B., Rosset. R., Bull. SOC. (73) Duncan, L. R., U. S. Atomic Energy Chim. France 1964, p. 2250.‘ ‘. Comm. HW-SA-2118, 12 pp. (1961). (109) Hersch, P., Sambucetti, C. J., ’ Chem. 15,’40 (1965). ’ (74) Durand, G., Tremillon, B., Bull. Deuringer, R., Chim. Anal. (Paris) (33) Brown, R. H., NASA Doc. N63- SOC.Chim. France 1963, p. 2867. 46, 31 (1964). 17618, 40 pp. (1963). (75) Eckfeldt, E. L., Shaffer, E. W., (110) Hiatt, V. G., J. Assoc. Ofic. Agr. (34) Brown. R. H.. Cloud. L. G.. Horn, ANAL.CHEM. 36, 2008 (1964). Chemists 47, 253 (1964). ~ S’. .J.. Ti.’ R. Aiomic Enerev-“ ‘Comm: (76) Ibid.. 37. 1534 119653.~, (111) Hibbs, J. &I., Nation, G. H., Analyst IDO-i6975,-12 pp. (1964). i77j Ibid.: p. i624. 89, 49 (1964). (35) Bubernak, J., Lew, &I. S., Matlack, (78) Ersepke, Z., Holek, T., Chem. Listy (112) Hill, H. A. O., Pratt, J. M., Wil- G. M.. ANAL.CHEM. 37. 1574 (1965). 58. 1325 (1964). liams, R. J. P., Chem. Ind. 1964, p. (36) Buck, R. P., Eldridge, R. iV., Ihid., (79) ‘Facsko; Gh,’, Radoi, I., Bul. Stiint. 147 p. 1242. Tehnic Inst. Politehnic Timisoara 5, (Ilij‘Hubbard, A. T., Anson, F. C., (37) Buechel, E., Chem. Ind. Jahrb. 391 (1960). ANAL.CHEM. 36. 723 (1964). (Solothum) 1962/63. D. 21. (80) Feldman, F. J., Christian, G. D., (114) Hubbard, A,’ T., Anson, F. C., J. (38) Busulini, L.,’ Niidi, E., Ric. Sci., Anal. Chim. Acta 33, 266 (1965). Electroanal. Chem. 9, 163 (1965). Rend. A 3, 807 (1963). (81) Fong, F. K., J. Chem. Phys. 41, (115) Israel, Y., Meites, L., Ibid., 8, 99 (39) Bvzova. R. P.. Kovalenko, P. N., 2291 (1964). (1964). ‘ Izv. tysshikh. Uchebn. Zavedenli, Khim: (82) Franklin, T. C., Franklin, N. F., J. (116) Iyer, R. H., Jain, H. C., Raminiah, i Khim. Tekhnol. 6, 557 (1963). Electroanal. Chem. 8, 310 (1964). XI. V.. Rao. C. L.. Radiochim. Acta 3. (40) Byzova, R. P., Kovalenko, P. N., (83) Fredericks, E. M., Harlow, G. A., 225 (1964). ’ Peredovye Metody Khim. Tekhno. i ANAL.CHEM. 36, 263 (1964). (117) Janata, J., Zvka, J., Collection Kontrolya Proizv. (Rostov-on-Don: Ros- (84) Fujinaga, T., Nagai, T., Okazaki, Czech. Chem. Commun. 30, 1723 (1965). tovsk. Univ.) Sb. 1964, p. 214. S., Takagi, C., Nippon Kagaku Zasshi (118) Johansson, G., Svensk. Keh. Tidskr. (41) Carman, R. L., Markham, J. J., 84, 941 (1963). 77. 76 (1965). Anal. Chim. Acta 31, 395 (1964). (85) Fujinaga, T., Takagi, C., Okazaki, (119j Johanssin, G., Talanta 11, 789 (42) Caton, R. D., Freund, H., ANAL. S., Kogyo Kagaku Zasshi 67, 1798 (1964). CHEM.36, 15 (1964). (1964). (120) Ibid., 12. 111 (1965). Ibid.: D. 163. (43) Charbonnier, M., Gauthier, J., (86) Gardiner, J. A., Collat, J. W., Inorg. i121j\---I ~ I r -- Courty, C., Bull. SOC.Chim. France Chem. 4, 1208 (1965). (122) Johnson, L. F., Neville, J. R., 1964, p. 525. (87) Gardner, R. D., Ward, C. H., Bancroft, R. W., Allen, T. H., NASA (44) Chem. Eng. News 43 (27), 32 (1965). Ashley, W. H., U. S. Atomic Energy Doc. H63-22411, 13 DD. (1963). (45) Chikryzova, E. G., Podolenko, A. A,, Comm. LA-3176, 9 pp. (1965). (123) Jones, H. C., Shilts, W.‘D., Dale, Zavodsk. Lab. 30. 791 (1964). (88) Gavrilko, Yu. AI., Kovalenko, P. N., J. Sf.,ANAL. CHEM. 37, 680 (1965). (46) Christensen, C. R.~,Anson, F. C., Bagdasarov, K. N., Peredovye Metody (124) Jones, J. G., Anson, F. C., Ibid., 36, ANAL.CHEM. 35, 205 (1963). Khim. Tekhnol. i Kontrolya Proizv. 1137 (1964). (47) Ibid., 36. 495 (1964). ( Rostov-on-Don, Rostovsk. Univ.) Sb. (125) Jovanovic, M. S., Jovanovic, B. (48) Christian, G. D., Ibid., 37, 1418 1964, p. 51. M., Stojiljkovic, R. M., Glasnik Hem. (1965). (89) Gavrilko, Yu. RL, Kovalenko, P. Drustva. Beograd 23/24, 511 (1959-61). (49) Christian, G. D., Microchem. J. 9, N., Bagdasarov, K. N., Zh. Analit. (126) Kalinowski, K., Fecko, J., Acta 16 (1965). Khim. 19, 1478 (1964). Polon. Pharm. 21, 247 (1964).

96 R 0 ANALYTICAL CHEMISTRY (127) Kalinowska, Z. E., Chem. Anal. (162) Lindbeck, M. R., Freund, H., (197) O’Donnell, T. A,, Stewart, D. F., (Warsaw) 9, 831 (1964). ANAL.CHEM. 37, 1647 (1965). Proc. Australian Conf. Electrochem., (128) Kalinowska, Z. L., Kochalska, J., (163) Lindstrom, F., Davis, J. B., Ibid., Ist, Sydney, Hobart Australia 1963, Acta Polon. Pharm. 21, 239 (1964). 36, 11 (1964). p. 332 (Publ. 1965). (129) Karklins. A.. S’eiss. A,. Latviias (164) Lipchinski, A., Kulev, I., Zh. (198) Ogino, H., Ebata, K., Tamamushi, I PSR Zinatnh Akad. Veitis, Kim. &r. Analit. Khim. 19. 357 (19641. R., Nakano, K., hfunemori, M., Bun- 1963, p. 124. (165) Lipner, H., ‘Witherspoon, L. R., seki Kagaku 11, 21R (1962). (130) Kekedy, L., Makkay, F., Studia Champeaux, v. c., ANAL.CHEM. 36, (199) Oglesby, D. M.,Anderson, L. B., Univ. Babes-Boluai, Ser. Chim. 7. 105 204 (1964). McDuffie, B., Reilley, C. N., ANAL. (1962). (166) Loodmaa, V. R., Loog, P. K., CHEM.37. 1317 119651. (131) Kemula, IT., Brachacxek, W., Chem. Palm, U. S’., Past, V. E., Reeben, V. A., (200). OglesLy, D. ~ M., ’ Omang, S. H., Anal. (Warsaw)8, 579 11963). Zh. Fiz. Khim. 38, 1374 (1964). Reilley, C. N., Ibid., 37, 1312 (1965). (132) Kesler, R. B., U. S. Patent 3,154,477 (167) Lott, P. F., 2. Chem. Educ. 42, (201) Onstott, E. I., U. S. Atomic (October 27, 1964). A261, A361 (1965). Energy Comm. LADC-5634, 7 pp. (133) King, D. AI., Bard, A. J., ANAL. W. A. A., (1962). 36, (168) McBryde, E., Graham, N. Electrochim. Acta 9, CHEM. 2351 (1964). Ott. W. L.. Talanta 11. 797 (1964). . (202) Osterwald, J., (134) King, 1). M.,Bard, A. J., J. Am. 451 (1964).\---- Chem. SOC.87, 419 (1965). (169) ’hlackereth, F. H. H., J: Sci.’Znstr. (203) Page,’J. A., Zinser, E. J., Talanta (135) Klees, G., German Patent 1,188,834 41, 38 (1964). 12, 1051 (1965). (March 11, 1965). (170) Mark. H. B.. Berlandi. F. J.. (204) Pamfilov, A. V., Skakun, E. G., (136) Ibid., 1,192,854 (May 13, 1965). ‘ BNAL. CHEM.36, 2062 (1964): Zh. Fiz. Khim. 37, 2603 (1963). (137) Koehly, G., Anal. Chim. Acta 33, (171) hIarshakov, I. K., Zakutskii, V. I., (205) Parker, W., Baumgartner, H., 418 (1965). Zh. Fiz. Khim. 38, 237 (1964). Nature 203, 715 (1964). (138) Kogan, F. I., Xaterialy 4-oi (172) Martin, F., Floret, A., Lemaitre, J., (206) Parker, W., Bildstein, H., Getoff, [Chetverto~]Xauchn. Konf. Aspirantov. Bull. SOC.Chim. France 1964, p. 1836. N., Nucl. Instr. Methods 26, 55 (1964). (Rostov-on-Don, Rostovsk. Univ.) Sb. (173) Sfartin, R. L., Grant, J. A., ANAL. (207) Patriarche, G., “Contributions a 1962, p. 135. CHEM.37. 644 11965). I’Analvse Coulometriaue.” Arscia. Brus- &’ (139) Kogan, F. I., Kovalenko, P. N., (174) Mashkovich, L. ’ A., Kuteinikov, sels, 1964. Ivanova. Z. I.. Peredovue Metodu Khim. A. F., SIaslova, T. P., Zavodsk. Lab. (208) Peltier, D., LeGuyader, M., 4’ekhnol. z Koktrolya PFotzv. (Rostov-on- 30. 788 (19641. Tacussel, J., Bull. SOC.Chim. France Don, Rostovsk. Unzv.) Sb. 1964, p. 65. (175j blather, W. B., Anson, F. C., ANAL. 1963, p. 2609. (140) Kogan, F. I., Kovalenko, P. X., CHEM.33, 132 (1961). (209) Penther, C. J., Notter, L. J., Ivanova, Z. I., Zh. Analit. Kham. 19, (176) Mathur, P. B., Balasuramanian, R., ANAL.CHEM. 36,283 (1964). 79 (1964). Lakshmanan, A. S., Indian J. Chem. (210) Pepersack, >I., Capel-Boute, C., (141) Ibzd., 20, 320 (1965). 3, 257 (1965). Decroly, C., Electrochim. Acta 10, 479 (142) Kolthoff, I. AI., Thomas, F. G., J. (177) ?*lead, K. K., llaricle, D. L., (1965). Electrochem. SOC.111, 1065 (1964). Streuli. C. A.. ANAL. CHEM. 37. 237 (211) Phillips, T. R., Johnson, E. G., (143) Kovalenko, P. N., E’eredovye hletody (1965): Woodward, H., ANAL.CHEM. 36, 450 Khzm. Tekhnol. z Kontrolya Pdozzv. (178) ;\leitea, L., J. Electroanal. Chem. 7, (1964). (Rostov-on-Don, Rostovsk. Unav.) Sb. 337 (1964). (212) Pilloni, G., Plazzogna, G., Ric. 1964. D. 29. (179) Me,i,tes, L., “Polarographic Tech- Sci., Rend. Sez. A 4, 27 (1964). (144) %d.,p. 162. niques, Interscience, New York, 1965. (213) Pribyl, >I., Slovak, Z., Mikrochim. (145) Kovalenko, P. N., Bashkova, L. F., (180) Merkle, F. H., Discher, C. A., Ichnoanal. Acta 1963, p. 1119. Elektrokhim. i Optich. Xetody Analiza ANAL.CHEY. 36, 1639 (1964). (214) Ibid., 1964, p. 1097. (Rostov-on-Don. Rostovsk. Univ.) Sb. (181) Mine Safety Appliances Co., Brit. (215) Proksch, E., Bildstein, H., Oesterr. 65, 1963, p. 86. -. . Patent 950,107 (Feb. 19, 1964). Chemiker-Ztg. 41 (1964). (14(5) Kovalenko, P. N. Chong-Bieuh,-- (216) Protsenko, G. P., Materialy 3-ei N., Geiderovich, 0. I., ‘Ukr. Khim. Zh. (182) hIirkin, 1‘. A., Zavodsk. Lab. 31,395 [Tret’ei] Nauchn. Konf. Aspirantov 30, 1344 (1964). (1965). (Rostov-on-Don, Rostovsk. Univ.) 1961, (147) Kovalenko, 1’. N. , hlusaelyants, (183) LIitchell, I. W., Saum, N. hl., p. 145. Hiltrop, C. L., Norelco Reptr. 11, 39 L. N., Izv. Vysshikh. Uchebi8. Zavednii, (217) Protsenko, G. P., Kovalenko, P. N., Khim. i Khim. Tekhnol. 8. 17 (1965). (1964). Ukr. Khim. Zh. 28, 522 (1962). (148) Kovalenko, P. N., ‘hIusaelya;its, (184) lliwa, T., Yoshimori, T., Takeuchi, (218) Purdy, W. C., “ElecttJ.oanalytica1 L. N., Ukr. Khim. Zh. 30, 753 (1964). T., Kogyo Kagaku Zasshi 67, 2045 Methods in Biochemistry, McGraw- (149) Kovalenko, P. N., Shchemeleva, (1964). Hill, New York, 1965. G. G.; Bagdasarov, K. X., Starodub- (185) Mora, E. B., Perez, F. P., Inform. (219) Pyatnitskii, I. V., Erisov, V. Yu., skaya, A. A., Elektrokhim. i Optich. Quim. ilnal. (Madrid) 18, 12 (1964). Ukr. Khim. Zh. 29, 1088 (1963). Metody Analiza (Rostov-on-Don, (186) Morris, ill. D., McKinney, P. S., (220) Rao, P. V. V., Udupa, H. V. K., Rostovsk. Univ.)Sb. 1963, p. 153. Woodbury, E. C., J. Electroanal. Elektrochim. Acta 10, 651 (1965). (150) Kozlovskii, 41. T., Tr. Komis. po Chem. 10, 85 (1965). (221) Rechnitz, G. A., hIcClure, J. E., dnalit. Khim., dkad. Nauk SSSR, (187) Mountcastle, W. R., Anal. Chim. ANAL.CHEM. 36, 2265 (1964). Inst. Geokhim. i Analit. Khim. 15, 132 Acta 32, 332 (1965). (222) Rechnitz, G. A., XIcClure, J. E., (1965). (188) Xountcastle, W. R., Dunlap, L. Tolanta 10, 417 (1963). (151) Krivis, A. F., Microchem. J. 5, 55 B., Thomason, P. F., ANAL.CHEM. 37, (223) Ibid., 12, 153 (1965). (1961). 336 (1965). (224) Rechnitz, G. A,, Srinivasan, K., (152) Kucera, Z., Sb. Vysoka Skoly (189) Muller, R. H., Ibid., 36, 123A ANAL.CHEM. 36, 2417 (1964). Chem.-Technol. Praze, Oddil Fak. Anorg. (1964). (225) Rechnitz, G. A., Srinivasan, K., Z. Org. Technol. 4, 55 (1960). (190) Xusaelyants, L. N., Kovalenko, Anal. Chem. 210, 9 (1965). (153) Kucerovsky, Z., Pribyl, M.,Siska, P. N., Elektrokhim. i Optich. Metody (226) Riccoboni, L., Oleari, L., Ric. Sci., X,Chem. Listy 59, 604 (1965). dnalaza ( Rostov-on-Don, Rostovsk. Univ.) Rend., Sez. A 3, 1031 (1963). (154) Kuleff, I., Lipcinsky, A., Z. Anal. Sb. 1963, p. 91. (227) Robinson, A. D., ISA Proc. Natl. Chem. 210, 37 (1965). (191) Nagai, T., hlatsuda, T., Suzuki, S., Anal. Instr. Symp. 8, 187 (1962). (155) Lagrange, P., Schwing, J., Bull. Nakano, K., Bunseki Kagaku, Shinpo (228) Roe, D. K., AN~L.CHEM. 36. 2371 SOC.Chim. France 1965, p. 2811. Sosetsu 1964, p. 28R. (1964). (156) Lagrou, A., T‘erbeek, F., J. Electro- (192) Narayanan, U. H., Sundararajan, (229) Rogers, H. R., Rev. Sci. Instr. 36, anal. Chem. 9, 184 (1965). K., Shenoy, S. B., Electroplating Metal 866 f 196.5). (157) Ibid., 10, 68 (1965). Finishing 16, 156, 259 (1963). (230) Rosa-Lda, E., Kem. Ind. (Zagreb) 12, (158) Langer, S. J., Haldeman, R. G., J. (193) Neilande, L., Karklins, A., Veiss, 747 (1963). Phys. Chem. 68, 962 (1964). V., Vanags, G., Latvijas PSR Zinatnu (231) Rousselet, F., Canal, J., Bull. SOC. (1%) Lektorskaya, N. A, Kovalenko, Akad. Vestas, Kzm. Ser. 1964, p. 7. Chim. France 1964, p. 1852. P. N., Elektrokhim. i Optichn. Metody (194) Nguyen, C., Kovalenko, P. N., (232) Sakurai,.. H.. Bunseki Kaoaku 11. 83 Analiza (Rostov-on-Don,Rostovsk. Univ.) Geiderovich, 0. I., Peredovye Metody (1962). Sb. 1963, p. 69. Khim. Tekhnol. i Kontrolya Proizv. (233) Santhanam, K. S. V., Krishnan, 60) Lektorskaya, N. A., Kovalenko, Ti. R., Z. Anal. Chem. 206, 33 (1964). 1’. N.. Peredovue Metodu Khim. Tekhnol. (Rostov-on-Don, Rostovsk. Univ.) Sb. (234) Santhanam, K. S. V., Krishnan, 1964, p. 69. z Kontrolva “ Proizo. (Rostov-on-Don, V. R.,2. Physik. Chem. (Frankfurt) 39, Rostovsk. Univ.) Sb. 1963, p. 61. (1951 Kovak. J. V. A.. Collection Czech.. 137 (1963). 61) Levenson, L. L., “Introduction to ~ Ckem. Commun. 30, 2703 (1965). (235) Schmid, E., Eschrich, H., AEC IClectroanalysis,” Butterworths, Lon- (196) O’Dom, G., Fernando, Q., ANAL. Accession No. 31374, Rept. No. NP- don, 1964. CHEM.37, 893 (1965). 14008, 11 pp. (1964).

VOL. 30, NO. 5, APRIL 1966 e 97 R (236) Schmid, E., Humblet, L., Eschrich, (261) Stroganova, N. S., Sdyarenko, Yu. (287) Valenta, P., Koryta, J., Nature H., AEC Accession No. 31373, Rept. S., Redkozem. Elementy, Akad. Nauk 203, 639 (1964). NO.NP-14007, 20 pp. (1964). SSSR, Inst. Geokhim. i Analit. Khim. (288) VanLoon, G., Page, J. A., Talanta

(237) Schoedler, C., Bull. SOC. Chim. 1963. D. 376. 12. 227 11965).\ ---, France 1964, p. 2401. (262) Sthck, W. A., Elving, P. J., J. Am. (289j Srassos, B. H., Berlandi, F. J., (238) Shain, I., Harrar, J. E., Booman Chem. SOC.86, 1229 (1964). Neal, T. E., Mark, H. B., ANAL.CHEM. G. L., ANAL.CHEM. 37, 1768 (1965). (263) Swofford, H. S., ANAL.CHEM. 37, 37, 1653 (1965). (239) Shemeleva, G. G., Kovalenko, P. N., 610 (1965). (290) Veneroni, R., Friesen, R., AEC Elektrokhim. i ODtich. Metodw Analiza (264) Szabadvary, F., Talanta 11, 593 Accession No. 7270. Reot. No. EUR-

A (Rostov-on-Don, ‘Rostovsk. Vniv.) Sb. f19641.\ --~ 2159.e., 60 pp. (1964). 1963, p. 82. (265) Tacussel, J., Compt. Rend. 258, (291) Voskresenskii, P. I., Talanta 12, (240) Shetanov, Kh., Konstantinova, M., 903 (1964). 11 (1965). Chvdarova, R., Compt. Rend. Acad. (266) Takahashi, T., Sakurai, N., Kogyo (292) Waclawik, J., Waszak, S., Chem. Bulgare Sei. 17, 721 (1964). Kagaku Zasshi 67, 1802 (1964). Anal. (Warsaw)8,865 (1963). (241) Shimojima, H., Takagi, J., J. Inorg. (267) Takahashi, T., Sakurai, H., Namiki, (293) Walker, J. A. J., Campion, P., Nucl. Chem. 26, 253 (1964). K., Bunseki Kagaku 13, 801 (1964). Analyst 90, 199 (1965). (242) Shinagawa, M., Nezu, H., Tamai, (268) Takao, H., Osaka Furitsu Kogyo- (294) Ward, G. A., Wright, C. M., J. T., Bunseki Kagaku 12, 836 (1963). Shoreikan Hokoku No. 30, 15 (1963). Electroanal. Chem. 8, 302 (1964). 10, Y.. Bunseki (295) White, L. R., Kesler, R. B., (243) Shiobara, Y., Ibid., 1290 (1961). (269) Takata, Muto.,I G., (244) Shirvington, P. J., Florence, T. M., Kagaku 14,‘ 259’(1965). Hardacker, K. W., TAPPI 47, 129 Harle, A. J., Austr. J. Chem. 17, 1072 (270) Ibid., p. 543. (1964). f (296) Wilson, C. L., Wilson, D. W., Ed., \--1964). --I (271) Takeuchi, T., Suzuki, M., Ishii, D., (245) Shropshire, J. A., J. Electroanal. Saito, K., Fujishima, I., Fukasawa, “Comprehensive Analytical Chemistry. Chem. 9, 90 (1965). T., Tanaka, T., Yoshimori, T., Mem. Electrical Methods,” Vol. 2a, Elsevier, (246) Shvedov, V. P., Antonov, P. G., Fac. Eng. Nagoya Univ. 15, 1 (1963). New York, 1964. Radiokhimiya 5, 616 (1963). (272) Takeuchi, T., Yoshimori, T., Kato, (297) Wise, E. N., U. S. Atomic Energy (247) Siebert, H., Z. Anal. Chem. 206, T., Bunseki Kagaku 12, 840 (1963). Comm. TID-20548, 8 pp. (1964). 20 (1964). (273) Tanaka, M.. Ibid..,. w. 840. (298) Wise, W. M., Williams, J. P., (248) Skrivelis, J., Veiss, A., Latvijas (274j Ibid., p.’ 897. ANAL.CHEM. 36, 19 (1964). PSR Zinatnu Akad. Vestis, Kim. Ser. (275) Thomason, P. F., AEC Accession (299) Ibid., p. 1863. 1963, p. 449. No. 2219. ReDt. KO. ORNL-P-636, (300) Ibid., 37, 1292 (1965). (249) Skrynnikova, G. N., Govorova, L. 18 oo. f 1964). (301) Wittick, J. J., Rechnitz, G. A., M.,Matveeva, N. I., Tr. Vses. Nauchn.- (276)’+olgyessy, J., Jesenak, V., Braun, Ibid., 37, 816 (1965). Issled. Inst. PO Pererabotke i Ispol’z. T., Hradil, M,, Chem. Zvesti 19, 465 (302) Wood, K. I., Ibid., 37, 442 (1965). Topliva No. 13, 200 (1964). (1966). (303) Wotring, A. W., Keeney, W. W., (250) Slovak, Z., Pribyl, M.. Z. Anal. (277) Tomlinson, L., Anal. Chim. Acta Proc. Natl. Anal. Instr. Sump. 8, 207 Chem. 211, 247 (1965). 31, 545 (1964). (1962). (251) Smith, G., Barnett, G. A., J. Inorg. (304) Yoshimori, T., Kori, S., Takeuchi, (278) Tribalat, S., Nofidi, D., Compt. T., Bunseki Kagaku 13, 309 (1964). iVucl. Chem. 27, 975 (1965). Rend. 1964. D. 3477. (252) Solon, E., Bard, A. J., J. Am. Chem. (305) Yoshimori, T., Miwa, T., Takeuchi, (279) Tso, T.’ b., Chu, P. L., Hua Hsueh T., Talanta 11, 993 (1964). SOC.86, 1926 (1964). Hsueh Pao 31, 86 (1965). (253) Solon, E., Bard, A. J., J. Phys. (306) Zaslavskaya, L. V., Ivanova, N. V., Chem. 68, 1144 (1964). (280) Tso, T. C., Li, H. L., Sun, C. C., Popova, N. M., Spektral’n. i Khim. (254) Soucek, J., Chem. Prumysl 13, 470 Ibid., 30, 301 (1964). Metodv Analiza Materialov, Sb. Metodik (1963). (281) Tso, T. C., Li, H. L., Sun, C. C., 1964, b. 107. (255) Spritzer, 11. S., Costa, J. M., K’o Hsueh T’una Pao 1964. I). 163. (307) Zolotareva, L. V., Kovalenko, P. Elving, P. J., ANAL. CHEM. 37, 211 (282) Tsuji, K., Eisei Shikehiho Kenkyu N., Zh. Analit. Khim. 19, 731 (1964). (1965). Hokoku No. 80, 29 (1962). (308) Zozulya, A. P., Novikova, E. V., (256) Steed. K. C.. Fransman.,, F.. Anal. (283) Ibid.. No. 81. 13 (1963). Ibid., 18, 1380 (1963). ‘ Chim. Ada 32, 472 (1965). (284j Tsybenko, V. I., ‘Peredovye Metody (309) Zugravescu, P. Gh., Sandulescu, D., (257) Stenina, N. l., Agasyan, P. K., Khim. Tekhnol. i Kontrolya Proizv. Rev. Chim. (Bucharest) 15, 40 (1964). Zh. Analit. Khim. 20, 196 (1965). (Rostov-on-Don, Rostovsk. Univ.) Sb. (310) Zuman, P., “Organic Polarographic (258) Ibid., p. 351. 1964, p. 275. Analysis,” Macmillan, New York, 1964. (259) Stock, J. T., “Amperometric Titra- (285) Tsyvenkova, T. V., Kovalenko, tions.” Interscience. New York. 1965. P. N., ‘Ivanova, Z. I., Zh. Analit. Khim. (260) Stre&, C. A.; Cincotta, ’J. J., 18, 1222 (1963). WORKsupported by the Robert A. Welch RIaricle, D. L., Mead, K. K., ANAL. (286) Turner, W. R., Elving, P. J., Foundation and the National Science CHEY.36, 1371 (1964). ANAL.CHEM. 37, 207 (1965). Foundation (GP-1921).

98 R ANALYTICAL CHEMISTRY