动态pH连接-毛细管电泳法测定和表征饮品中7种酚酸

Determination and profiling of seven phenolic acids in wines and beverages by capillary electrophoresis with dynamic pH junction

建立了一种用于测定和表征葡萄酒和饮料中7种酚酸的毛细管电泳结合动态pH在线富集的方法.将含有7种酚酸的样品溶解于pH为3.5的磷酸盐背景电解质中,它与作为电泳分离介质的背景电解质不同(pH9.2的20mmol/L硼酸缓冲液中含有体积分数25%的甲醇).系统地研究了影响在线富集和分析的各种实验因素(检测波长、运行背景电解液中甲醇的含量、分离电压和进样时间等).在最优条件下,7种酚酸的工作曲线的相关系数均大于0.9992,检出限LOD(S/N=3)为0.014~0.027μg/mL,加标回收率在80%~130%.样品制备步骤非常简单,只需要用酸性背景电解质对样品进行稀释和过滤,1个样品的分析(包括样品处理和电泳分析)在大约16min内完成.这种方法成功应用于葡萄酒和果汁中酚酸的测定和表征.

A method of capillary electrophoresis combined with dynamic pH junction online concentration for determination and profiling of seven phenolic acids in wines and beverages was developed.The sample containing 7phenolic acids was dissolved in the specific background electrolyte,phosphate buffer at pH 3.5,which was different from the background electrolyte in electrophoretic separation medium,20mmol/L borate buffer containing 25%methanol(V/V)at pH 9.2.The experimental factors influencing online concentration and analysis were systematically studied,induding detection wavelength,fraction of methanol in running background electrolyte,applied voltage and injection time.Under optimized conditions,the correlation coefficients for the calibration lines of the 7phenolic acids were greater than 0.9992,with limits of detection(S/N=3)in the range of 0.014~0.027μg/mL.The recoveries for the selected phenolic acids were in the range of 80%~130%.The sample preparation step was so simple that only dilution with acidic background electrolyte as well as filtration were required,leading to the analysis time for one sample 16min,including sample treatment and electrophoretic analysis.The developedmethod was applied to determination and profiling of 7phenolic acids in wines and beverages.