Abstract:

To address the issues of oxidative degradation of vitamin C and severe chromatographic interference in fruit and vegetable matrices，this study optimized the reduction procedure and chromatographic conditions of the existing high-performance liquid chromatography（HPLC）method. The results showed that limits of detection for L-ascorbic acid and D-isoascorbic acid before reduction，and for L-ascorbic acid and D-isoascorbic acid after reduction，were as low as 0.14，0.13，0.35，and 0.32 mg·kg^-1，respectively. Both isomers exhibited good linearity within the respective concentration ranges，with coefficient of determination（R2）of no less than 0.999 9. In the three-level（low，medium，and high）spiked recovery experiments（n=7），the recovery rates ranged from 90.0% to 106.0%，with relative standard deviations of no more than 2.5%. The improved method is simple in operation with less matrix interference，and can simultaneously determine the content of vitamin C before and after oxidation，making it suitable for batch detection and routine application for fruit and vegetable samples.

Key words: high-performance liquid chromatography, vitamin C, fruits and vegetables, limit of detection, recovery rate