DETERMINATION OF SULFITE AND ASCORBIC-ACID BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH ELECTROCHEMICAL DETECTION

A rapid HPLC method with electrochemical detection for the determination of free and total sulphite and ascorbic acid in beer and other beverages is presented. Interferences of these compounds are discussed, in addition to the behaviour in buffer solutions of different pH. Only a dilution step is required before injecting the sample into the chromatographic system. To obtain better specificity for these compounds, two different working electrodes (platinum for sulphite and carbon glass for ascorbic acid) with distinct potentials are used.