Polarographic Analysis of Diosgenin in Dioscorea zingiberensis C.H.Wright

目的:研究采用线性扫描极谱技术,测定薯蓣皂苷元(C_(27)H_(42)O_3,简称皂素)的分析方法。方法:用硫酸水解黄姜粉末,以乙醇提取薯蓣皂苷元,再用线性扫描极谱法进行测定。结果:在 pH=5.3±0.5的 B-R 缓冲溶液和0.1 mol·L^(-1)氯化钾底液中,薯蓣皂苷元产生极谱还原波,其一阶导数波的峰电位在-1.05 V(vs.SCE)处,峰电流与薯蓣皂苷元的浓度在一定浓度范围内有良好的线性关系,r=0.9989。建立了薯蓣皂苷元的极谱分析方法,成功地测定了黄姜中的薯蓣皂苷元,并讨论了极谱波的产生机理。结论:方法简便可行,结果准确可靠。本方法对黄姜中薯蓣皂苷元的测定结果与 Liebermann-Barcharad 光度法一致。

Objective ：To study an analytical method of diosgenin of Dioscorea zingiberensis by linear scan polarography. Methods：The powder in Dioscorea zingiberensis was hydrolyzed in sulfuric acid. The diosgenin was extracted with alcohol. The diosgenin was determinated by linear scan polarography. Results：Diosgenin yielded a polarographic deoxidized wave with the potential - 1.05 V in pH = 5.3 ±0.5 B - R buffer solution,0. 1 mol· L^-1 KCl supporting electrolyte. The first - order derivative peak current of the wave was rectilinear to diosgenin concentration in the range of 1.0 × 10^-6 -8.0 × 10^-5 mol · L^-1 and the correlation coefficient is 0. 9989. The limit of detection is 1.0 × 10^-6 mol ·L^-1. The mechanism of the polarographic wave of diosgenin is discussed. Conclusion： The proposed method is simple and reliable. And analytical result on diosgenin in Dioscorea zingiberensis is accordant to Liebermann - Barcharad spectrophotometry.