THE USE OF PULSED AMPEROMETRY COMBINED WITH ION-EXCLUSION CHROMATOGRAPHY FOR THE SIMULTANEOUS ANALYSIS OF ASCORBIC-ACID AND SULFITE

Initial attempts to monitor ascorbic acid and sulfite, in a beer matrix, by combining ion-exclusion chromatography with a pulsed amperometric detector using a single applied voltage to the platinum working electrode, were unsuccessful. Alternatively, good chromatograms for the separation of the two antioxidants were achieved utilizing a standard, amperometric cell. However, remarkably superior results were observed when this standard cell was operated in a pulsed mode and cleaning cycles were continually applied throughout the analysis. The working electrode stability and precision have been examined. Preliminary spike recovery data indicate acceptable accuracy for the method. Comparisons of this method to standard reference methods are currently ongoing.