Recently several attempts have been made to adapt polarographic methods to the study of molten salt systems. The principal need has been for an physico-chemical procedure which could be operated in situated temperature up to 1000°C. The technique contains several difficulties different from the case of ordinary polarography in aquous solution, due to high temperature, consequently severe corrosion, and anhydrous medium. Such technique and its recent process are clescrihed and some of the anomalous features of the results are discussed.

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The anodic stripping voltammetry, which has been developed recently, are reviewed with 8 references.The anodic stripping methods involve the depositing metal ions electrolytically on an electrode and the oxidizing the metals electrochemically.These are very sensitive for the determination of trace amounts of metal ions, and under favorable conditions have a lower limit of determination on the order of 10^-9M.In these analytical applications, all of these methods involve the electrodeposition of a metal from a dilute solution by some reproducible procedures.The amount so deposited then bears a known relation to the concentration of the metal ion in the solution and is measured in terms of an electrical signal produced by its complete or partial dissolution at more anodic potentials.The electrodes have been used in various types, e.g., mercury pools, hanging mercury drops and amalgamated platinum electrodes.W.Kemula and co-workers, have used the electrode and cell like Fig.1 in their experiments of anodic stripping voltammetry.Since in the application of the hanging mercury drop electrode to analytical determination of trace metals, the very dilute solutions were used, no mutual interaction of metals in mercury drop electrode was observed even in the presence of more than one metallic species. Application of this method to the study on the formation of intermetallic compounds can be illustrated with reference to the nickel-zinc system.In Fig.2 curves of dissolution of amalgams formed at the hanging mercury drop electrode are given.Calomel film on the hanging mercury drop electrode did not interfere with Ni oxidation.The intermetallic compo-unds do not form at concentration less than 10^-5M.W.Kemula and his co-workers have studied on the determination of Cu, Bi, Sb, Pb, Sn, In and Cd in highly pure zinc.It consists of a preliminary 3-5 minutes electro-lytic concentration of the metals on the hanging mercury drop electrode, and subsequent recording of the oxidation currents of the amalgams formed.When no chemical separation is necessary the total time of analysis does not exceed 90minutes.The lowest concentrations found in the zinc samples analyzed were:6.4×10^-5% Pb, 8.2×10^-6% Cd, 2×10^-5% Sb and 6.8×10^-4% In.(Fig.3, 4 and Table I).W.Kemula and his co-workers have studied on the rapid determination of Cu, Pb and Cd in U compounds (10^-6% Cd and 10^-5% Cu and Pb).The analysis time, dependent on the compound being analysed, is approximately 1-2 hours. The precision is about ±10%.The determination is performed in carbonate solution in which the UO₂(CO₃)₃^4- complex is reduced at -1.0V., which does not influence the reduction of ions with more positive reduction potentials.An investigation was made of the concentration range in which it was supposed that Cu, Pb and Cd carbonates would precipitate and interfere with the determination.This type of interference was observed when the concentrations of Cu exceeded 10^-6M and that of Cd and Pb exceeded 10^-5M.(Fig.5 and Table II.).R.Neeb has studied on the principle of the anodic amalgam voltammetry and the determination of small amounts of lead, cadmium, bismuth and thallium.After the electrolytic separation of metals at amalgamated platinum electrode and rapid resolution of the amalgams at more anodic potentials, reproducible results can be obtained for trace amounts of metals under controlled conditions by measuring the peak heights on the current-voltage curve.Detailed procedures for the determination of trace amounts of Pb, Cd, Li, and Tl are given.A.G.Stromberg and his co-worker used a platinum wire cathode, on which the mercury from saturated Hg(NO₃)₂solution was deposited, in the determination of 10^-8to 10^-7M Pb²⁺in 0.1N KCl.The s

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There was traced an analogy between polarographic methods and measurements of flow rate in a flowing system, which is composed of a hydraulic reservoir, pumps and a piston whose plunger can control the opening of pump-exits. A flow into its cylinder corresponds to the condenser current and a pumped flow corresponds to the electrolytic current. With these analogues DC, AC, SW and RF polarographic methods may be explained. But for current controlled polarography and Heyrovsky-Forejt oscillographic polarography the further composition of flowing system is necessary.

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The relationship between the a.c. polarographic peak height and the rate constant is experimentally investigated on the basis of the theory proposed by Karribara and Matsuda. The a.c. peak height is found to vary with the. reversibility function and a new simple and rapid method evaluating the rate constant k_s of electrode process at standard potential is proposed. For the electrode reaction between zinc in amalgam and zinc ion in 1M sodium hydroxide, the value for k_s was found to be 7.4×10-5 cm/sec.

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