Liquid chromatographic determination of non-volatile nitrosamines by post-column redox reactions and voltammetric detection at solid electrodes. Behaviour of the Ce(IV)-Ce(III) couple at gold, platinum and glassy carbon electrodes and suitability of the Ce(IV) reagent

Abstract

The suitability of Ce(IV) in acidic medium as post-column reagent in the liquid chromatographic (LC) amperometric determination of non-volatile nitrosamines was investigated by studying the Ce(IV)-Ce(III) couple with a rotating disk electrode, whose behavior approaches the operational conditions of a “channel-thin-layer” cell with solid electrodes as frequently used for liquid chromatographic detectors. The conditional kinetic parameters k 0′ and α were evaluated at platinum, glassy carbon and gold electrodes. Gold was found to be the most suitable material. The reaction between Ce(IV) and NO − 2 (which is the product of the decomposition of the nitrosamines in warm acidic solution) was considered. The biamperometric behavior of the system was studied by varying the concentration of Ce(III) in presence of excess of Ce(IV) and also by producing Ce(III) by reaction between Ce(IV) and nitrite.