Determination of ascorbic and dehydroascorbic acids in blood plasma and serum by liquid chromatography

A liquid-chromatography (LC) method with ultraviolet detection for measuring ascorbic (AA) and dehydroascorbic acid (DHA) in human blood and serum was studied. The method used an ODS reversed-phase column and cetyltrimethyl ammonium bromide as an ion-pairing agent. AA was measured before and after the reduction of DHA with dithiothreitol. The absence of interferences resulting from hemolysis products was verified and also the stability of the ascorbic acid in metaphosphoric acid extracts. The analytical parameters, linearity (1-80 micrograms/ml), accuracy (recovery, 96.7-100.7%) and precision (C.V. = 3.1%), show that the method is reliable and adequate for measuring the total vitamin C content in serum and plasma.