Liquid Chromatographic Determination of Non-volatile Nitrosamines by Post-column Redox Reactions and Voltammetric Detection at Solid Electrodes. Study of a Flow Reactor System Based on the Ce(IV) Reagent.

The behaviour of an on-line post-column reactor system based on the use of Ce(IV) reagent in acidic medium for the liquid chromatographic amperometric determination of non-volatile nitrosamines has been investigated in a two-line flow manifold coupled with a flow-through voltammetric detector equipped with twin gold electrodes for both mono- and biamperometric detection modes. The physical dispersion coefficients and the time domain parameters of the current peak responses obtained by flow injections of both Ce(III) and nitrite in aqueous and mixed water-acetonitrile carriers were used to evaluate the performance of the flow reactor elements. Mono- and biamperometric measurements allowed the determination of the linear dynamic ranges, the sensitivities and the detection limits of nitrite under different experimental conditions with respect to the composition of the carrier liquid and the temperature of the reactor system. Peak standard deviations were calculated and used to predict the effects of band broadening and tailing induced by the reactor system on the chromatographic bands.