乙基紫褪色分光光度法测定七叶皂苷钠

Fading spectrophotometric method for determination of sodium aescinate with ethyl violet

在pH4．1的BR缓冲溶液中，乙基紫（EV）与七叶皂苷钠（SA）作用，形成离子缔合物，溶液颜色发生明显褪色。其最大褪色波长位于594nm处．七叶皂苷钠的质量浓度与褪色强度呈正比，七叶皂苷钠的质量浓度在0．15～35．0ug／mL范围内遵守比尔定律，相关系数为R=0．9995，摩尔吸光系数为2．5×10^4L·mol^-1·cm^-1，检出限为45．8ng／mL。该方法已用于片剂和尿样中七叶皂苷钠的测定。

In pH 4.1 BR buffer medium, ethyl violet （EV） reacts with sodium aescinate（SA） to form an ion-association complex. The maximum fading wavelength is at 594 um. The fading intensity is proportional to the concentration of sodium aescinate. The concentration of sodium aescinate in the range of 0.15 - 35.0ug/mL obeys beer＇s law. The correlation coefficient is 0. 9995, the molar absorptivity is 2.5 × 10^4 L·mol^-1·cm^-1 and the detection limit is 45.8 ng/mL. The method has high sensitivity and low detection limit, and has been applied to the determination of sodium aescinate in tablets samples and urine samples with satisfactory results.