胶束毛细管电泳在线富集技术测定那格列奈中痕量杂质时分峰现象的研究

目的:探究采用胶束毛细管电泳(MEKC)并结合在线推扫富集技术检测样品时出现分峰现象的原因。方法:以应用胶束毛细管电泳在线富集技术测定那格列奈原料中痕量杂质为例,讨论了背景缓冲液 pH、表面活性剂浓度(分别讨论了 SDS 及CTAB)、离子强度与进样时间对分峰现象的影响。结果:背景缓冲溶液 pH、表面活性剂浓度、离子强度不同时,出现分峰时的进样量不同,富集倍数不同;其他条件一定时,进样量对分峰的出现也有影响。应用此技术测定那格列奈原料中痕量杂质时,最佳富集倍数达到了200倍。结论:用 MEKC 并结合推扫法测定样品时,要对电泳条件进行逐一优化,以筛选出可获得最佳富集效果,满足检测灵敏度,并避免分峰的实验条件。

Study on splitting peaks during determination of trace impurities in nateglinide by MEKC with on- line concentration

Objective:To study the appearance of splitting peaks created by micelle capillary electrophoresis (MEKC)with on-line sweeping concentration technique.Methods:When trace impurities in nateglinide were de- termined with this method,the effects of the pH of running buffer,the concentration of surfactant(sodium dodecyl sulfate and cetyltrimethylammonium bromide were discussed,respectively),ion strength and injection time on the appearance of splitting peaks were discussed.Results:When the pH of running buffer,the concentration of surfac- tant and ion strength were different,the injection time of the appearance of splitting peaks and the concentration multiple were different.When other conditions were same,the injection capacity also effected on the appearance of the splitting peaks.When trace impurities in nateglinide were determined with this method,the best concentration multiple was 200.Conclusions:When the sample was determined by MEKC with on-line sweeping concentration method,the conditions of electrophoresis should be discussed to select the conditions,under these conditions,the best result of concentration and the satisfied detection limit was obtained,the appearance of splitting peaks were a- voided.