毛细管电泳-电化学检测法测定鸡蛋中残留四环素类抗生素

Antiseptics Trace Determination of Tetracyclines in Eggs by Capillary Electrophoresis with Electrochemical Detection

本研究运用毛细管电泳-电化学检测法(CE-ED)对鸡蛋中残留的四环素(TC)、土霉素(OTC)进行快速测定分析。考察了缓冲液浓度和pH值、TW-20、盐浓度、分离电压、进样时间、检测电位等因素对分离检测的影响。结果表明,TW-20体积分数为2.5%时,在检测电位为1.2V,20mmol/L缓冲溶液(pH2.6),25kV分离电压,进样8s的条件下,TC和OTC有很好的分离效果。TC和OTC的线性范围分别为:2.0×10-6～5.0×10-4g/ml和8.0×10-6～3.0×10-4g/ml,检测限分别为1.9×10-8g/ml和4.1×10-8g/ml。

A capillary electrophoresis technique with electrochemical detection （CE-ED） for determination of tetracyclines （TC） and oxytetracycline （OTC） in eggs was described in this study. Effects of several factors, such as the pH value and concentration of running buffer, concentration of Tween-20, separation voltage, injection time and current potential applied to the working electrode, were investigated to find the optimum conditions. Well-defined separation of TC and OTC was achieved in the running sodium phosphate monobasic （pH 2.6）. A carbon-disk electrode used as the working electrode exhibits good response at ＋1.20 V （vs. SCE（saturated calomel electrode）） for the analytes. The detection limits （S/N=3）for TC, OTC are 1.9×10^-8 g/ml, 4.1×10^-8 g/ml, respecratively.