Sensitivity limits for the current-step method for zinc and cadmium amalgam stripping

• Published in: Journal of electroanalytical chemistry 1966, Vol.11 (1), p.54-61
• Main Authors: Vincent, H.A., Wish, E.N.
• Format: Article
• Language: English
• ISSN: 0368-1874; 2590-2946
• DOI: 10.1016/0022-0728(66)80058-X

Constant-current stripping with potential—time readout indication is applied to zinc and cadmium amalgams In order that the anodic transition time for either of these elements be a correct indication of the amount of the element present in the system, the potential of the working electrode must be controlled by an electrochemical couple involving that element, and the electrode poising must be maintained while nearly 100% of that element is stripped electrically from the electrode. The exchange current densities for zinc and cadmium amalgam electrode systems are taken as measures of the electrode poising ability for these systems. It was found that the exchange current density for an electrode system must exceed 10 −9 A/cm 2 in order that the system poise an electrode long enough to give a measurable transition time plateau on the potential—time readout- This minimum exchange current density value increases when competitive electrode systems are present. Detection limits for zinc and cadmium in solution were calculated and depend on the size of the sample.