毛细管区带电泳-电化学法检测洋葱中活性成分

采用毛细管区带电泳-电化学检测法(CE-ED)同时测定了洋葱中芥子酸、槲皮素和原儿茶酸的含量，研究了电极电位、运行液浓度和分离电压等实验参数对分离检测的影响.在优化的条件下，以直径300 μm的碳圆盘电极为工作电极，电极电位为＋950 mV(vs.SCE), 在pH 9.0的40 mmol/L的硼酸运行缓冲液中，上述3组分在25 min内可完全分离.芥子酸、槲皮素和原儿茶酸的浓度分别在2.0×10^-7-1.0×10^-4g/mL、2.0×10^-7-5.0×10^-5g/mL和5.0×10 ^-7-5.0×10^-5g/mL的范围内与峰电流呈良好线性关系，检测下限分别为1.5×10^-7g/mL、1.6×10^-7g/mL和3.6×10^-7g/mL，7次测得的三种组分峰高的相对标准偏差分别为2.70%、4.65%和1.73%，三次测得的平均回收率分别为102.2%、105.5%和100.9% .

Determination of Sinapic Acid,Quercetin and Protocatechuic Acid in Allium cepa Linn by Capillary Zone Electrophoresis with Electrochemical Detection

A simultaneous determination of sinapic acid, quercetin and protocatechuic acid in Allium cepa Linn by capillary aone electrophoresis with electrochemical detection was reported. The parameters affecting the separation and detection such as detection potential, separation voltage and concentration of running buffer were evaluated. Under the optimum conditions, the analytes were baseline separated within 25 min in a borax buffer (PH=9.0). Good linear relationship was established between peak current and concentration of analytes in the range of 2.0×10^-7-1.0×10^-4g/mL for sinapic acid, 2.0×10^-7-5.0×10^-5g/mL for quercetin, and 5.0×10^-7-5.0×10 ^-5g/mL for protocatechuic acid. The detection limit (S/N=3) is 1.5×10^-7g/mL,1.6×10^-7g/mL and 3.6×10^-7g/mL respectively for these three analytes. This method has been used for the determination of active ingredients in allium cepa linn with satisfactory results.