分光光度法测定大黄中大黄素的含量

DETERMINATION OF EMODIN IN RHUBARB BY SPECTROPHOTOMETRY

建立了10倍量90％乙醇回流提取、15倍量乙酸乙脂二次回流提取，最后用碱提酸沉法制备高纯度大黄素的方法。用改进的分光光度法对纯化后产品进行测定，大黄素含量达85．41％。显色剂为5mol／L的NaOH溶液，检测波长为530nm，该显色体系的线性范围为1～400μg／mL，相关系数为0．9993，平均回收率为99．57％，RSD为1．31％（n=4）。

The new purifying method of emodin from rhubarb was established. 10 - fold 90% ethanol and 15 - fold ethyl acetate were used as the first and second circumfluence solvents, alkaline extraction and acid precipitation was finally used to purify emodin. The content of purified emodin determined by the improved spectrophotometry was 85.41%. The colour reagent was 5 mol/L NaOH, and the detection wavelength was 530 nm. The linear range of system was 1 -400 μg/mL, and regression coefficient was 0. 9993. The average recovery was 99.57% and the RSD was 1.31% （n =4）.