非水毛细管电泳法测定藤黄中藤黄酸的含量

Determination of gambogic acid in Gamboge by non-aqueous capillary electrophoresis

藤黄酸（gambogicacid，GA）等环氧杂蒽酮类化合物的水溶性差，可通过非水毛细管电泳（NOR—aqueouscap—illaryelectrophoresis，NACE）分析。本文系统地考察了添加20％～60％（v／v）的甲醇或乙腈的运行电解质溶液对藤黄提取液中藤黄酸分离的影响。比较了不同的运行电解质溶液、运行电解质溶液浓度、pH、添加剂口一环糊精的浓度、分离温度及分离电压的影响，建立了测定藤黄药材中藤黄酸含量的非水毛细管电泳方法。在40％乙腈、10mmol／L β-环糊精、20mmol／L四硼酸钠（pH9．86）为运行电解质溶液、分离电压为10kV、分离温度为30℃、检测波长为280nm的条件下进行测定。结果表明，藤黄酸在2～2000mg／L范围内线性关系良好，相关系数为0．9996，检出限（S／N=3）为2mg／L。将本方法应用于越南、泰国、缅甸、印度4个产地的藤黄药材中藤黄酸的含量测定，测得含量为1．67—472．40me,／g（相对标准偏差（RsD）为1．12％～2．60％），其中越南产藤黄中藤黄酸含量低，其他产地藤黄中藤黄酸的含量高。实际藤黄样品中藤黄酸的加标回收率为95．2％～105．6％。非水毛细管电泳方法简单、快速、重现性好，可用于藤黄药材中藤黄酸的含量测定。

Gambogic acid （GA）, a kind of caged xanthones, has low solubility in water. A non-aqueous capillary electrophoresis （NACE） was established for the determination of GA in Gamboge based on the optimized conditions. The effect of 20%- 60% methanol or acetonitrile spiked in running solution was investigated. The effects of compositions, concentration, pH, additives like β-cyclodextrin in running buffer were thoroughly studied. Applied voltage and applied temperature were also observed. Optimal electrophoretic conditions were as follows： 20 mmoL/L sodium borohydride solution （pH 9. 86） containing 40% （v/v） acetonitrile, 10 mmol/L fl-cyclodextrin as running buffer, applied voltage of 10 kV, capillary temperature of 30 ℃ and detection wavelength of 280 nm. The calibration curve had good linearity in the range of 2-2 000 mg/L with the correlation coefficient of 0. 999 6. The limit of quantification （ S/N = 3 ） of the method was 2 mg/L. The quantifications of GA in Gamboge from different producing places including Vietnam, Thailand, Burma, India were 1.67 - 472. 40 mg/g with the RSD （ n = 3 ） of 1.12% -2.60%. The content of Gamboge from Vietnam is obviously low while the others are high. The recoveries of GA spiked in real samples ranged from 95.2% to 105.6%. The method of NACE is simple, efficient and of good reproducibility, can be served as a novel reference to identify and control the quality of Gamboge.