双波长叠加法测定样品中槲皮素含量

Determination of Quercetin by Dual-wavelength Overlapping Spectrophotometry

在pH=7.45的B-R缓冲介质中,槲皮素在256nm和368nm波长处有两个强度不等的吸收峰,实验发现两个峰的吸光度值之和与槲皮素的浓度呈良好的线性关系,据此提出了双波长叠加分光光度法测定微量槲皮素的新方法。槲皮素的质量浓度在0.84～42μg.mL-1范围内符合比耳定律,表观摩尔吸光系数高达4.24×104 L.mol-1.cm-1,比单波长法提高了86.8%,检出限为0.30μg.L-1。方法应用于测定降脂宁胶囊中槲皮素的含量,测定值的相对标准偏差为3.23%,用标准加入法测得此方法的回收率在95.2%～102.7%之间。

An UV-spectrophotometric method for the determination of quercetin was reported.In a B-R buffer medium of pH=7.45,two absorption peaks at the wavelength of 256 nm and 368 nm were observed,and the sum of absorbance at these two peaks showed good linearity with quercetin concentration in the range of 0.84～42.0 μg／5mL-1.The apparent molar absorptivity was 4.24×104 L／5mol-1／5cm-1 which was 86.8% higher than that obtained under the conventional single wavelength measurement mode.Detection limit of the proposed method was found to be 0.30 μg／5mL-1.The method was applied to the determination of quercetin in Jiangzhining capsules.The relative standard deviation of results was no more than 3.23%,and the values of recovery test obtained by the standard addition method were in the range of 95.2%～102.7%.