在线扫集-毛细管胶束电动色谱法对石榴与石榴叶中没食子酸含量的测定

Determination of Gallic Acid in Pomegranate and Its Leaves by On-line Sweeping Micellar Electrokinetic Chromatography

建立了一种在线扫集-胶束电动色谱法测定没食子酸的新方法。考察了背景溶液pH值、十二烷基硫酸钠（SDS）浓度、样品基体组成和进样时间对富集效果的影响。使用未涂层的毛细管柱（48．5cm×75μmi．d．，有效柱长40cm），pH9．0的20mmol／L硼酸盐＋50mmol／LSDS为背景溶液，在紫外检测波长272nm、运行电压18kV的条件下，200s内的富集倍数可达20倍。线性范围为0．62—10．30mg／L（r=0．999），检出限（S／N=3）为0．08mg／L，平均回收率为104％。没食子酸迁移时间和峰面积的相对标准偏差分别为1．2％和1．6％。方法快速、准确可靠、灵敏度高、重复性好，可检测石榴不同部位和石榴叶以及饮料中没食子酸的含量。

An on-line sweeping-micellar electrokinetic chromatographic method was developed for the determination of gallic acid. Effect of pH in background solution, concentration of SDS, matrix composition of the sample and injection time was investigated. The concentration factor for gallic acid could reach 20 times within 200 s by a non-coating fused-silica capillary column （48.5 cm ×75μm, effective length 40 cm）, using 20 mmol/L borate（pH 9.0） ＋50 mmol/L SDS as the running buffer and 272 nm as detection wavelength under 18 kV separation voltage. The calibration curve of gallic acid was linear in the range of 0. 62 - 10. 30 mg/L with correlation coefficient of 0. 999. The limit of detection（S/N = 3 ） was 0. 08 mg/L and the average recovery was 104%. The relative standard deviations（RSDs） for migration time and peak area of gallic acid were 1.2% and 1.6% , respectively. The proposed method was rapid, accurate and had high sensitivity and good reproducibility. It could be applied for the determination of gallic acid in pomegranate and its leaves as well as beverages.