John A. Page

A hydrogen-nitrogen gas coulometer

Abstract The hydrogen-oxygen gas coulometer yields a negative error at small current densities. A hydrogen-nitrogen gas coulometer, employing a hydrazine sulphate electrolyte, and free from this error, is described. A new form of the gas coulometer, employing the hydrazine sulphate electrolyte and suitable for the accurate integration of small quantities of electricity (5 to 20 coulombs) has been developed.

The coulometry and polarography of iridiumIV

Abstract The coulometric and polarographic behaviour of iridium IV has been investigated. In a 0.2 M hydrochloric acid electrolyte, at potentials negative enough to prevent the oxidation of the mercury, the indium gives a diffusion current plateau suitable for polarographic determinations. Electrolysis at a controlled electrode potential shows that the reduction requires one electron per mole, and has been used for the coulometric determination of 3- to 17-mg amounts of iridium. The behaviour of iridium in other electrolytes has also been investigated.

Voltammetric Reduction of Nickel and Cobalt Dimethylglyoximate

The determination of cobalt and nickel in aqueous solutions by stripping voltammetry after adsorptive preconcentration is an established procedure. The method is highly sensitive, but there is some controversy concerning the reasons for the excellent sensitivity. Using a variety of voltammetric techniques, we have determined that the reduction of nickel dimethylglyoximate in an ammonia buffer is consistent with an overall process involving 16 or possibly 18 electrons. This hypothesis is confirmed by independently measuring the total quantity of metal adsorptively deposited on the mercury electrode and comparing the amount with the quantity of electricity required for its reduction.

Studies in the polarography and coulometry of the aquo and chloride complexes of rhodium(III)

Abstract The polarography of the aquo and chloride species of rhodium(III) has been investigated. The aquo complex was prepared by fuming in perchloric acid, and the various chloride complexes were prepared by heating in the presence of chloride ion. In all cases, polarography gave irreversible diffusion controlled waves. It is essential that the solution constituents be carefully reproduced for analytical polarography, and that the solutions be stabilised by heating, because equilibrium is established very slowly at room temperature. Mercury cathode electrolysis at a controlled potential showed that the polarographic reduction step involved 3 electrons. This is used as the basis of a coulometric determination of 1.5- to 15-mg amounts of rhodium in 0.2–0.4 M chloride electrolyte at a potential of −0.2 V vs . SCE.

The direct polarography of aluminium

Abstract The direct polarography of aluminium has been investigated in a 0.10M tetrabutylammonium chloride (tbNH4Cl) electrolyte. Adjustment of pH prior to polarography is accomplished by a constant current electrolysis of the acid solution using a platinum cathode and a silver anode. The pH can be adjusted precisely and the aluminium waves are highly reproducible. For analytical determinations a pH of 3.70 has been arbitrarily chosen for concentrations of aluminium up to 2mM. The method is applied to the analysis of a zinc-base alloy, using both controlled potential electrolysis and amalgamometry to separate interfering elements.

Coulometric reduction of iridium(IV) in perchloric acid media

Abstract A previous report that high results for the coulometry of iridium(IV) could be explained on the basis of a secondary reduction process is shown to be incorrect.