KIO_3用于药片与饮料中抗坏血酸的示波测定  

Application of KIO_3 to Oscillographic Determination of Vc in a Troche and a Drink

作　　者：郑建斌[1] 倪宏刚[1] 张宏芳[1] 

机构地区：[1]西北大学分析科学研究所

出　　处：《应用化学》2005年第7期726-729,共4页Chinese Journal of Applied Chemistry

基　　金：国家自然科学基金资助项目(20275030);陕西省自然科学基金项目(2004B20);陕西省教育厅专项科研基金资助项目(01JK076)

摘　　要：在0.2mol/LNaOH底液中,碘酸钾在示波图阴极支-0.6V(vs.SCE)和-1.6V处产生2个切口。当向上述体系中逐渐加入还原性物质抗坏血酸时,-1.6V处切口的深度随抗坏血酸加入量的增加而变浅。根据KIO3的这一示波特性,建立了用二次微分简易示波伏安法间接测定抗坏血酸的新方法,并将该法用于Vc片剂及酷儿饮料中Vc含量的测定。在选定的实验条件下,碘酸钾在二次微分简易示波图上的峰高与抗坏血酸浓度在3.0×10-6～4.5×10-5mol/L范围内呈线性关系,回归方程为:h(v)=258-2.839×105c(mol/L),R=0.9954,检出限为2.0×10-6mol/L,对于3.0×10-5mol/LVc的5次测定的相对标准偏差RSD为2.9%,回收率为98.9%。氧化还原体系中的示波测定方法能用于某些没有示波活性的物质测定。In a 0.2 mol/L NaOH solution, KIO_(3) can yield two peaks at -0.6 V(vs.SCE) and -1.6 V on the cathode of oscillogram. The reduction at -1.6 V is quite sensitive, its depth would get shallow with the (increase) of Vc because of the reaction between Vc and KIO_(3). Based on this oscillographic character, a new method, second order differential simple oscillographic voltammetry for the determination of Vc in a troche and a drink containing Vc is established in this paper. Under the optimal experimental condition, a linear response was observed in the range 3.0×10^(-6)～4.5×10^(-5) mol/L with a correlation (coefficient) R=0.995 4 and a (detection) limit 2.0×10^(-6) mol/L for Vc. The relative standard deviation(RSD) and average recovery for the determination of 3.0×10^(-5) mol/L Vc are 2.9% and 98.9%(n=5), respec-(tively). Thus, the oscillographic determination method in a redox system can be applied to the determination of some non-active substances in oscillographic analysis, and so it is an actually useful approach for enlarging the application field of oscillographic analysis.

关 键 词：KIO3 VC 示波分析 示波测定 药物分析 

分 类 号：O657.1[理学—分析化学]