茶叶中无机阴离子的毛细管电泳分离间接检测方法的研究

Indirect Determination of Inorganic Anions in Tea by Capillary Electrophoresis

建立了毛细管电泳分离测定茶叶中Cl^-、NO2^-、NO3^-、SO4^2-、F^-及HPO4^2-的方法.通过研究分离电压、背景电解质和电渗流改性剂的浓度、pH的影响优化了分析条件.在优化条件下,6种无机阴离子在10min内得到完全分离,各组分迁移时间和峰高的相对标准偏差（RSD）分别为1.9%～4.7%和1.2%～3.8%,检出限为0.11～0.82 mg/L.通过分析实际样品并做加标回收实验验证了该方法的可行性,Cl^-、NO3^-、SO4^2-及HPO4^2-的回收率为93%～98%.

An indirect method has been developed for the determination of Cl^-, NO2^-, NO3^-, SO4^2-, F^-, and HPO4^2- in tea by capillary electrophoresis. The influences of pH, separation voltage, and concentrations of electroosmotic flow modifier, CTAB and background electrolyte were investigated. Under optimized conditions, those anions could be completely separated within 10 rain. The detection limits for Cl^-, NO2^-, NO3^-, SO4^2- , F^-, and HPO4^2- were 0.23,0. 16, 0. 11,0. 32, 0. 27 and 0.82 mg/L, respectively. The recoveries of spikng Cl^- , NO3^- , SO4^2- and HPO4^2- in various types of real tea samples ranged from 93%- 98% .