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采用滴涂法制备了壳聚糖修饰石墨圆盘电极，并用于Ｌ－抗坏血酸（ＬＡＡ）的半微分伏安法测定。研究了电解液种类及酸度、膜厚度、富集电位及时间、扫速和温度等因素对伏安曲线的影响，获得了较为优化的测试条件。在０．２０ｍｏｌ／Ｌ ＮａＨ２ＰＯ４－Ｎａ２ＨＰＯ４（ｐＨ６．０）缓冲液中，ＬＡＡ的浓度在 １． ０×１０－５～ ６． ０ × １０－４ ｍｏｌ／Ｌ范围内与氧化峰电流呈良好线性关系（ ｒ＝０．９９９７），检测限达６．７×１０－７ｍｏｌ／Ｌ；生物体内常见的干扰物质如亚硝酸盐、多巴胺、葡萄糖等不干扰测定。 ９次测得电极在含 ５．０ ×１０－５ ｍｏｌ／Ｌ ＬＡＡ试液中峰电流的 ＲＳＤ为３．６％，回收率为９６．４％～１０２．８％（ ｎ＝５）。已成功用于维生素Ｃ片剂和人血清中 ＬＡＡ的测定。
Chitosan modified graphite disk electrode was prepared by drop-coating method and used for semi-differential voltammetric determination of L-ascorbic acid (LAA). The effects of electrolyte type, acidity, membrane thickness, enrichment potential and time, sweep rate and temperature on the voltammetry curves were investigated. The optimized test conditions were obtained. In 0.20mol / L NaH2PO4-Na2HPO4 (pH6.0) buffer, LAA concentration of 1. 0 × 10-5 ~ 6. In the range of 0 × 10-4 mol / L, there was a good linear relationship with the oxidation peak current (r = 0.9997), the detection limit was 6.7 × 10-7mol / L. The common interfering substances in vivo such as nitrite, Dopamine, glucose, etc. do not interfere with the determination. The RSD of the peak currents of the 9 electrodes measured in the LAA solution containing 5.0 × 10-5 mol / L was 3.6% and the recovery was 96.4% -102.8% (n = 5). It has been successfully used in the determination of LAA in vitamin C tablets and human serum.