碘与淀粉的相互作用及在Vc分析中的应用

本文探讨了碘与淀粉的相互作用以及碘－淀粉显色体系的稳定性。结果表明：在碘量一定时，体系的吸光度随淀粉用量的增大而增大，最后趋向稳定；在淀粉量一定时，体系的吸光度随碘用量的增大而增大，最后亦趋向稳定。碘－淀粉显色体系很不稳定，吸光度随时间呈比较明显的下降趋势，但加入复合表面活性剂可以使显色体系的稳定性大大提高。在上述结果的基础上，我们建立了测定Ｖｃ的新方法，此法具有简单、快捷、试剂易得、灵敏度高以及对浑浊试液不必分离即可直接测定等优点。该法的灵敏度为０．２５μｇ／ｍｌ，对１μｇ／ｍｌ的Ｖｃ试液进行平行测定，１０次平行测定结果的相对标准偏差为８．８６％，加标回收率为９０．５％－９３．６％，用于番石榴汁饮料中Ｖｃ的测定，结果满意。

The Interaction Between Iodine and Starch and Tts Application to Analysis of Vc

This paper goes into the interaction between Iodine and starch as well as the stability of Iodine-Starch clour system. The experiment results show that as the amount of iodine is constant, Absorbance (A) of the System goes up with the amount of starch and shows a tendency to stability at last;As Starch constant,A goes up with iodine also. The system is not stable,A goes down with time,but mixing surfactants can stablize it. According to above experiment results,We devise a new analysis method of Vc. The method is simplesfast,Its sensitivity is 0. 25ug/ml; RSD of 1ug/ml is 8. 86%(ten times), the rate of recovery is from 90.5% to 93. 6% ; The new method is used for determining Vc of Fanshiliu beverage with Satisfactory results.