Measurement of ascorbic acid in human aqueous humour and plasma and bovine aqueous humour by high-performance liquid chromatography with electrochemical detection.

High-performance liquid chromatography (HPLC) on ODS silica with cetyltrimethylammonium bromide as an ion-pairing reagent and electrochemical detection (ECD) was used to determine ascorbic acid in bovine and human aqueous humour and human plasma. Hydroquinone was used as the internal standard. A calibration curve plotted with ascorbic acid concentrations in the range 0.5-5 micrograms ml-1 for peak height versus internal standard peak height had a correlation coefficient of 0.998. The RSD (precision) between analyses of the same diluted sample was 1.5% and the RSD (reproducibility) between analyses of separate aliquots of the same sample of aqueous humour was 1.6%.