甲基橙褪色动力学光度法测定槲皮素的研究

Study on determination of quercetin by discoloring kinetic spectrophotometry of methyl orange

基于稀H2SO4介质中，槲皮素对KB如氧化甲基橙褪色反应的明显催化作用，建立了测定痕量槲皮素的动力学光度法。在选定的条件下，方法的线性范围为0～0．05mg／L，表观摩尔吸光系数为4．52×10^6L·mol^-1·cm^-1，检出限为0．0012mg/L。利用此法测定了银杏叶和中药制剂慢严舒柠中的槲皮素，加标回收率为95％～106．7％，相对标准偏差小于3．3％。

A catalytic kinetic spectrophotometric method for the determination of quercetin was proposed, and the method was based on the catalysis of quercetin to the discoloring reaction of methyl orange oxidized by potassium bromate in the dilute sulfuric acid solution. Under the condition selected, the linear range of 0 - 0.05 mg/L is obtained for quercetin with the detection limit of 0.0012 mg/L and the apparent molar absorption coefficient of 4.52×10^6L·mol^-1·cm^-1. The method was applied to the determination of quercetin in the gingko leaves and the Chinese medicine, the recovery was 95% - 106.7% and the RSD of the method was less than 3.3% with satisfactory results.