Fast HPLC–ECD analysis of ascorbic acid, dehydroascorbic acid and uric acid

A robust and rapid high-pressure liquid chromatography–electrochemical detection (HPLC–ECD) method was developed and validated for the accurate determination of ascorbic acid (AA) and uric acid (UA), in human plasma. Dehydroascorbic acid (DHAA) was indirectly measured by subtracting native ascorbic acid from total ascorbic acid concentrations; the latter was obtained after chemical reduction. A stable electrochemical active internal standard (homogentisic acid) was added for the accurate quantification of the analytes. The analyses were performed on a reverse-phase column with traditional HPLC and ultra-HPLC (UHPLC). The UHPLC method showed increased sensitivity with detection limit of 0.05 ng for both AA and UA, 2 times lower compared to conventional HPLC. UHPLC also reduced run times fourfold with less waste generation. Both assays showed good accuracy and precision, the intra- and inter-day CVs of AA and UA analysis are less than 7%.