饮料中还原型维生素C与总维生素C测定方法的研究

DETERMINATION OF REDUCED AND TOTAL VITAMIN C IN BEVERAGE BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

目的 建立简便快速的高效液相色谱测定饮料中的还原型VC与总VC的方法。方法：反相高效液相色谱法，Waters515高效液相色谱仪，Waters2996二极管阵列检测器，检测波长245nm，Atlantisd C18柱，流动相为0．1％乙酸水溶液。样品不经二硫苏糖醇（dithiothreitol，DTT）还原直接测定还原型VC；经DTT还原后测定总VC。结果：线性范围为1～20μg／ml。测定还原型VC的RSD2．5％～7．4％，平均回收率为96．8％；测定总VC的RSD2．7％～8．6％，平均回收率为99．8％。还原法测定总VC结果与荧光法比较，差异无显著性（P〉0．5）。结论：该方法前处理简单，重现性好。测定准确、简便、快速，适于食品中的还原型VC与总VC的测定。

Objective： To establish a simple, accurate method of HPLC to determine reduced and total ascorbic acid （VC） in beverage. Method： The method was developed with the condition as follows： Atlantis dC18 column （4.6mm× 150mm, 5μm）, 0.1% acetic acid as the mobile phase with the speed of 1.0 ml/min. Reduced and total VC was detected before and after DTT reduction respectively. Results： The common linear range was 1--20μg/ml. RSD was 2.5%--7.4 % for reduced VC and 2.7%-8.6% for total VC, and average recovery rate was 96.8% and 99.8% respectively. No significant difference was found between HPLC and the standard fluorescence method （P〉0.05）. Conclusion： This method is simple, accurate, feasible for determination of reduced and total VC of beverage.