紫外分光光度法测定曲札茋苷的解离常数

Determination of Dissociation Constants of 3,5,3′,4′-tetrahydroxy-stilbene-3′-O-Glu-coside(THSG) by UV Spectrophotometry

目的:采用紫外分光光度法测定曲札茋苷的解离常数。方法:将曲札茋苷溶于一系列Britton-Robinson缓冲溶液中,并选择在曲札茋苷适合的波长处分别测定它们的吸光度并计算其pKa值。结果:以319、325和330nm作为分析波长,计算出曲札茋苷一级电离常数pKa1=7.90;以330、340和350nm作为分析波长,计算出曲札茋苷的二级电离常数pKa2=10.41。结论:该方法操作简单易行,重现性良好。曲札茋苷离解常数测定结果对进一步研究曲札茋苷的提取分离、制剂研究及其在生物体内的吸收、分布和代谢过程具有重要的参考意义。

Objective： To determine dissociation constants of THSG by UV spectrophotometry. Method： THSG was dissolved in Britton - Robinson buffer solutions of different pH values and the absorbance was calculated according to the suitable wavelenths. Results： The pKal value was found to be 7.90 in Britton - Robinson buffer solutions using wavelengths 319, 325 and 330nm for the determination, and the pKa2 value was found to be 10.41 in Britton -Robinson buffer solutions using wavelengths 330, 340 and 350nm for the determination. Conclusion： The present method is convenient and practicable. This study lay the foundation for the investigations of absorption, distribution and metabolism of the durg.