紫外分光光度法测定橙汁中维生素C的含量

摘要

[目的]为市售饮料中维生素C(Vc)的科学测定提供参考.[方法]利用Cu2+催化溶解氧氧化Vc,建立紫外分光光度法测定橙汁中还原型Vc的方法,并对测定条件进行优化.[结果]采用磷酸和醋酸混酸溶液(3∶7,V∶V)作稳定剂,Cu2+为催化剂,70 ℃恒温水浴中,测定市售橙汁饮品中Vc的含量,标准曲线方程为y=0.071 4x+0.135 0,线性相关系数为0.999 5.该方法精密度RSD(n=5)为0.35%,加标回收率为98.5%.[结论]建立了紫外分光光度法测定橙汁中Vc的方法,该方法简单、快速,结果令人满意.%[Objective] Tth aim was to provide refereneces for the scientific determination of Vitamin C (Vc) in sold beverage. [Method]With Cu2+ as catalyst to oxidize Vc, the method to determine reduced Vc in orange juice by UV spectrophotometry was constructed, and then the determination conditions were optimized. [ Result] With the mixed solution of phosphoric acid and acetic acid (3∶7, V∶ V) as the stabiliz er, Cu2+ as catalyst and in the 70 ℃ water-circulator bath, Vc content in the sold orange juice was determined, the standard curve equation was y = 0.071 4x + 0.135 0, the linear correlation coefficient was 0.999 5, the precision RSD( n = 5 ) was 0.35％ and recovery rate was 98.5％. [ Conclusion] The method to determine Vc in orange juice by UV spectrophotometry was constructed, which was simple and fiast and whose results were very satisfying.