维生素C(抗坏血酸)经Cu2+氧化为脱氢抗坏血酸,在一定条件下与邻苯二胺反应生成具有荧光的物质.基于此,建立了一种新的测定维生素C的荧光分析法.实验中对氧化剂Cu2+及邻苯二胺的用量、缓冲液介质等进行了优化,在优化条件下,维生素C的浓度在0.05～5.00 μg/mL与其对应荧光强度呈良好的线性关系,相关系数R2=0.998 7;检出限为0.03 μg/mL；对3个不同浓度的样品进行加标回收实验,其回收率为88.91％ ～92.25％；对1.0μg/mL的样品测定3次,测定结果的相对标准偏差为1.98％.将该法用于西红柿、青椒等水果及蔬菜中维生素C含量的测定,结果令人满意.%Vitamin C(ascorbic acid) was oxidated by Cu2+ to DHAA which reacted with o-phenylenediamine in buffer solution to form a fluorescent product. Based on this oxidation-reduction reaction, a new spectrofluorimetric method for determining ascorbic acid was proposed. In experiments, the amount of oxidant ( Cu 2+ ), o-phenylenediamine, and buffer solution were optimized. Under the optimal condition, the concentration of vitamin C was 0. 05 -5. 00 μg/mL, the linear correlation coefficient R2 =0. 998 7, and the detection limit was 0.03 μg/mL. In standard recovery test of three samples with different concentration, the recovery rate of this method is in between 88. 91% and 92. 25% , and the relative standard deviation was 1.98% (n =3) by measuring three times to the sample of concentration of 1.0 μg/mL. When the method was applied to the determination of vitamin C in tomatoes and green peppers, the results for analysis are satisfactory.
展开▼
