酶标仪三波长比色法定量测定大豆总皂甙

本研究采用豆粕的乙醇提取物以水饱和正丁醇萃取纯化得到大豆总皂甙,用香草醛-高氯酸体系显色,再采用酶标仪结合三波长法测定和校正吸光值,以期建立大豆总皂甙酶标仪三波长比色定量测定法。结果表明:本方法大豆总皂甙一次提取效率为95.985%,两次合并提取效率为99.510%;萃取纯化效率为90%;皂甙浓度与吸光度之间存在极显著的线性关系,最低检出限浓度为19.667μg/ml;精密度实验的变异系数为2.7%;平均加标样回收率为95.519%,其变异系数为5.719%;可有效克服皂甙显色反应不稳定、吸光值会随时间延长而下降的问题,并在一定程度上消除干扰物质和本底漂移对定量分析造成的影响,使测定的精度进一步提高。本方法具有操作简便、重现性好、精密度高,适于大批量样品测定以及产品生产的质量控制及监测等特点。

Determination of Soysaponins Content by Three-waveleangth Colorimetry on High Performance Microplate Spectrophotometer

The total soysaponins were extracted from defatted soybean meal with alcohol and purified by the n-butanol resolution saturated with water, then stained by HClO4-vanilin staining method. The saponin absorbency was determined by high performanc microplate spectrophotometer and revised by three-wavelength method. The aim of this experiment was to build a method of determining the total soysaponins of soybean samples. The result showed that one time extracting rate was 95.985%, the total extraction rate of two times was 99.510%, and the purification rate was 90%. Markedly significant linear regressive relationship was found between the absorbency and concentration of total saponins. The lowest detection limit was 19.667μg/ml. The coefficient of variation (cv) of the accuracy experiment was 2.7%. The average recovery rate was 95.519% with cv being 5.719%. The new determining method is reliable, which could efficiently overcome the staining reaction instability and the declination of absorbency with the time, and avoid or eliminate, to a degree, the influence of the interfering components and the peak floating.