LAUSR

Abstract The objective of the study was to develop a new method for the determination of total vitamin C and dehydroascorbic acid contents in food using the differential pulse polarography technique, and to compare achieved results to those obtained with the proposed reference method applying HPLC with spectrophotometric detection. Dithiothreitol was used to reduce dehydroascorbic acid into l -ascorbic acid. Interference due to the presence of dithiothreitol during polarographic determination of l -ascorbic acid was efficiently eliminated by clarification of the sample solution with Carrez reagent. Validation of the polarographic method indicates its usefulness for the analysis of foods products that do not contain isoascorbic acid. The coefficient of variation for the analysis of l -ascorbic acid and total vitamin C content ranges from 1.86% to 6.98%, Horrat values from 0.41 to 0.89 and average recovery of l -ascorbic acid ranges from 98% to 104%. Results obtained using the developed method are characterised by high compatibility with those obtained with the HPLC reference method, indicating equivalence of both methods, and in conclusion, the method was deemed fit for purpose for measuring total vitamin C and dehydroascorbic acid in foods.