褪色分光光度法测定七叶皂苷钠

Fading spectrophotometric method for the determination of sodium aescinate

目的:建立褪色分光光度法测定七叶皂苷钠。方法:在 pH 3.5～4.2的 Britton—Robinson 缓冲溶液中,七叶皂苷钠与夜蓝反应,形成离子缔合物时能使染料发生明显的褪色作用。产生最大褪色波长为614 nm,并且吸收度降低与七叶皂苷钠浓度成正比。结果:七叶皂苷钠浓度在0.25～20.0μg·mL^(-1)范围内符合比耳定律,摩尔吸光系数为1.4×10~4L·mol^(-1)·cm^(-1),方法具有较高的灵敏度,其检出限为75 ng·mL^(-1),研究了共存物质的影响,表明方法选择性好。结论:此法简便、准确、灵敏,可用于片剂和尿样中七叶皂苷钠的测定。

Objective： To establish a fading spectrophotometric method for determination of sodium aescinate. Methods： In pH 3.5 - 4.2 Britton - Robinson buffer medium, sodium aescinate can bind with night blue dye to form the binding products and a fading reaction appears. The maximum fading wavelength locates at 614 nm. The concentration of sodium aescinate is directly proportional to the degree of fading （ - △A）. Results： The concentration of sodium aescinate in the range of 0.25 - 20.0 μg ·mL^- 1 obeys Beer＇s law. The maximum molar absorption coefficient（emax） is 1. 4×10^4 L · mol ^-1· cm^ -1. The method has very high sensitivity. The detection limit is 75 ng · mL^- 1. Their influence of some coexisting substances was investigated. The method has better selectivity. Conclusion ： The method is simple, accurate, sensitive and applied to the determination of trace amounts of sodium aescinate in tablet samples and urine samples with satisfactory results.