甘草酸二钾的极谱法测定及其应用

The detection of dipotassium glycyrrhizinate based on polarograph and its application

目的:建立非油脂性化妆品样品中甘草酸二钾的电化学分析方法.方法:用滴汞电极检测甘草酸二钾在Britton-Robinson(B-R)缓冲溶液中的电化学信号,对检测条件进行优化,并应用于实际化妆品样品的分析检测.结果:甘草酸二钾在滴汞电极上于-1.44V(vs.SCE)处在上产生一个灵敏的二阶导数极谱还原峰.在最佳条件下,二阶导数峰电流值(ip')同甘草酸二钾的浓度在1.11×10-6～3.34×10-5mol/L范围内呈良好的线性关系,线性回归方程为ip'(nA)=211.65C(μmol/L)+25.67,相关系数r为0.995,检出限为9.34×10-7mol/L,用于非油脂性模拟化妆品中的检测回收率为98.4%～103.6%.结论:本方法操作简便、信号灵敏、选择性好,可应用于化妆品样品的检测.

Objective：To establish a sensitive and simple electrochemical method for the determination of dipotassium glycyrrhizinate（DG） in cosmetic samples. Methods：The electrochemical response of DG in Britton - Robinson（ B - R） buffer solution was detected by polarograph. The experimental conditions were optimized, and the method was used to detect the content of DG in samples. Results： Under the optimized conditions, a sensitive 2ed derivative polarographic wave peak was observed at - 1.44 V （vs. SCE）. the peak current （ip^n） was found to have a linear relationship with the concentration of DG in the range of 1.11 ×10^-4 - 3.34 ×10^-5 mol/L, ip^n（nA） = 211.65C （μmol/L） ＋ 25.67, r = 0. 9952, and the limit of detection of this method was detected to be 9.34 ×10^-7 mol/L. The recovery of this method was found to be 98.4% - 103.6% when it was used in the detection of DG in mimic sample of non - grease cosmetics. Conclusion： The method is simple, sensitive, accurate and tolerant to many foreign substances, and can be used for the real sample determination.