瞬间等速电泳-毛细管区带电泳检测头孢比肟及其注射剂中的微量N-甲基吡咯烷

Determination of trace N-methylpyrrolidine in cefepime and its injections by transient isotachophoresis-capillary zone electrophoresis

目的用瞬间等速电泳(t-ITP)-毛细管区带电泳(CZE)技术在线富积并检测头孢比肟及其注射剂中的微量N-甲基吡咯烷(NMP)。方法采用非涂层弹性石英毛细管;背景电解质为0.03mol/L咪唑溶液(pH4.7);间接紫外检测。以高浓度的探针离子兼作前导离子,供试品溶液中的头孢比肟、氢离子或精氨酸作为终结离子,在毛细管前端构建t-ITP体系以产生样品自身堆积效应并富积NMP^+。结果可大体积进样以增加灵敏度并同时避免NMP^+区带的展宽。本文方法的定量限约为2μg/mL,相当于头孢比肟量的0.01%,检测灵敏度比文献报道的CZE法和离子色谱法高10倍以上。结论该方法适用于对头孢比肟及其注射剂中的微量NMP的高灵敏度检测。

Objective A capillary zone electrophoresis（CZE） with on-line preconcentration method was established to determinate trace N-Methylpyrrolidine（NMP） in cefepime and its injections. Methods The terminating-type sample self-stacking was based on transient isotachophoresis in which high concentration of probe ion served as leading ion, and native cefepime, hydrogen ion or arginine as the terminating ion. Results High sensitivity can be obtained with large volume injection, avoiding NMP~ zone distortion. Best results were achieved with the background electrolyte constituting of 0.03mol/L imidazole （pH4.7） in a single bare fused-silica capillary with indirect UV detection. The limit of quantitation was about 2μg/mL, which equivalent to 0.01% of cefepime. The proposed method is at least 10 times more sensitive than conventional CZE and ion chromatography. Conclusion The proposed method is suitable for highly sensitive detection of trace NMP in cefepime and its injection samples.