黄芩及其制剂中黄芩素和黄芩甙的

用毛细管区带电泳 -电化学检测法测定了黄芩及其制剂中黄芩素和黄芩甙的含量。研究了电极电位、电解液酸度和浓度、电泳电压及进样时间等对电泳的影响 ,得到了较为优化的测定条件。以直径为300μm的碳圆盘电极为检测电极 ,电极电位为0.90V(vsSCE) ,在100mmol/L硼酸盐缓冲液(pH9.0)中 ,上述两组分在8min内完全分离。黄芩素和黄芩甙浓度与电泳峰电流分别在5.0×10 -7～1.0×10 -3mol/L和1.0×10 -6～1.0×10 -3mol/L范围内呈良好线性 ,检出限分别为2.24×10 -7mol/L和5.48×10 -7mol/L。7次测定分别含5.0×10 -4mol/L黄芩素和黄芩甙试样溶液 ,峰高的相对标准偏差分别为3.53%和4.03%。

Determination of Baicalein and Baicalin in Radix Scutellariae and Its Pharmaceutical Preparations by Capillary Zone Electrophoresis with Electrochemical Detection

A method for the simultaneous determination of baicalein andbaicalin in Radix Scutellariae and its pharmaceutical preparations by capillary zone electrophoresis with electrochemical detection(CE－ED) is reported. Several parameters affecting the CE－ED determination were studied, including the potential of working electrode, pH and concentration of running buffer, separation voltage and injection time. Baicalein and baicalin could be well separated in a 100 mmol/L borate buffer(pH 9.0) within 8 min. A carbon disc electrode of 30 μm diameter was used as the working electrode at potential of 0.90 V (vs SCE). There is an excellent linearity between peak current and concentration in the range of 5.0× 10－7～1.0×10－3 mol/L for baicalein and 1.0×10－6～1.0×10－3 mol/L for baicalin. The detection limits(S/N=3) are 2.24× 10－7 mol/L and 5.48×10－7 mol/L ,respectively. The relative standard deviations of peak currents(n=7) for sample containing 5.0×10－4 mol/L for each of the two analytes are 3.53％ and 4.03％ for baicalein and baicalin, respectively.