ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Possibilities of absolute chronoamperometric determination. 2. Influence of parallel chemical-reaction and shielding of the hanging mercury drop electrode

D. Bustin

Department of Analytical Chemistry, Slovak Technical University, CS-81237 Bratislava

Abstract: Basis for application of chronoamperometry as an absolute determina­tion method of electroactive substances is the separation of the signal component limited by the linear diffusion from that limited either by spheri­cal or cylindrical contribution to the total flux of the determined substance to the hanging mercury drop electrode. Using the thick-wall capillary for its realization the results are loaded by proportional error following from electrode shielding by capillary wall. The sufficient difference of half-wave potentials is a prerequisite in the case of application of chronoamperometry for absolute determination of two electroactive substances. The analysis of that reducing substance which is the second one in the order is performed after subtracting the current of the first species. Its result is by the rule less precise than with the analysis of one-component sample. The absolute chronoamperometric determination is compared with the controlled potential coulometry. Apart from the greater rate of the analysis it seems to be more advantageous to use chronoamperometry in the cases (which are relatively often in the practice) when the analytically used elec­trode reaction is complicated by slow chemical processes.

Full paper in Portable Document Format: 412a215.pdf

Chemical Papers 41 (2) 215–225 (1987)