DETERMINATION OF L-ASCORBIC-ACID IN FOODS BY CAPILLARY-ZONE-ELECTROPHORESIS

A new capillary zone electrophoresis (CZE) assay for L-ascorbic acid ( L-AA) in foods has been developed. The Korean Food Coder for the analy sis of L-AA employs 2,4-dinitrophenylhydrazine (DNP) and high-performa nce liquid chromatographic (HPLC) methods, This study was carried out to determine the L-AA by CZE and the results were compared with those of DNP and HPLC methods. CZE demonstrated good efficiency as well as r apid analysis, Analysis was done within 2 min with efficiency approach ing 78,000. CE separation was achieved with an untreated fused silica capillary of 27 cm total length x 57 mu m I.D. using a sodium berate b uffer. UV absorption of solutes was detected at 245 nm and 265 nm. The electric field was 556 V/cm, Under the optimum conditions, L-AA in va rious foods was determined. A 512-channel diode-array detector was use d to confirm the L-AA peak. The coefficients of variation of the migra tion time and the peak area were less than 0.5% and 1.2%, respectively . The limit of detection (S/N = 3) for quantitative determination was 0.25 mu g/ml. Good linearity and recovery were also obtained with a co rrelation coefficient r = 0.993 and 95.0-98.6% recovery. Considering t he results of our study, CE method should be highly suitable for the d etermination of L-AA in foods. (C) 1997 Elsevier Science B.V.