苦参碱-氨基黑体系的显色反应及其分析应用

Color reaction of matrine-amido black system and its analytical application

在pH=7．6的BR缓冲体系中，氨基黑与苦参碱发生反应，形成离子缔合物时，溶液颜色发生改变．其最大显色波长位于532nm处，在最大显色波长处，苦参碱浓度与溶液的显色呈良好的线性关系，可用于苦参碱的测定．苦参碱的浓度为0．08×10～3．0×10g／mL范围内符合比尔定律，相关系数R=0．9992，摩尔吸光系数为6．46×10^6L／（mol·cm），检出限为0．025μg／mL．方法快速、灵敏、操作简便，可用于片剂和尿液中苦参碱的测定，结果满意。

Into a 10 mL volumetric flask were added 1.0 mL of Amido black dyes solution, suitable amounts of matrine and 1.0 mL of pH 7.6 BR buffer solution. After 10 min the mixture was diluted to the mark with water and mixed thoroughly and set the solution aside for 15 rain. In pH 7.6 BR buffer medium, Amido black reacts with matrine to form ion association complex. The maximum positive wavelength locates at 532 nm. The positive intensity is directly proportional to the concentration of matrine. The concentration of matrine in the range of 0.08 × 10^6 ～3.0 ×10^-6 g/mL obeys Beer＇s Law. The correlation coefficient is 0. 999 2, and the molar absorptivities （s） is 6.46×10^4 L/（mol·cm）. The detection limit was 0.025μg/mL. The composition ratio of amido black with matrinein the ion-association complex was established by using Job＇s method of continuous variation and molar ratio method, the result showed that matrine., amido black is 2：1. The effects of various foreign substances such as talc powder, lactose, glucose, starch, dextrin, protein and some metal ions on the determination of matrine were investigated. The tolerable amount of foreign species was found when the relative error was within ±5%. It can be seen that certain amounts of glucide, amino acids, protein and common metal ions did not interfere with the determination. Therefore, the method has better selectivity which can be used for the determination of actual samples. The method has high sensitivity and low detection limit. It has been applied to the determination of matrine in tablets samples and urine samples with satisfactory results.