Katayama H, Ishihama Y, Asakawa N
Department of Analytical Chemistry, Analytical Research Laboratories, Eisai Co., Ltd., Ibaraki, Japan.
Anal Chem. 1998 Dec 15;70(24):5272-7. doi: 10.1021/ac980522l.
A coated capillary modified with a cationic polymer was developed by using a novel coating procedure, successive multiple ionic-polymer (SMIL) coating. The SMIL coating was achieved by first attaching the cationic polymer to the capillary inner wall, and then the anionic polymer to the cationic polymer layer, and finally the cationic polymer to the anionic polymer layer. The stability of Polybrene (PB)-modified capillary made by SMIL coating was remarkably improved in comparison with a conventional PB-modified capillary. It endured during 600 replicate analyses and also showed strong stability against 1 M NaOH and 0.1 M HCl. The relative standard deviation of the run-to-run, day-to-day, and capillary-to-capillary coating was all below 1%, and good reproducibilities were obtained. The PB-modified capillary made by SMIL coating was applied to the basic protein analyses. It gave good performances for the protein analyses even when the pH of the electrolyte was near the isoelectric point (pI) of the protein. In addition, 0.1 M NaOH rinse prior to the sample injection allowed the reproducible analysis of a highly adsorptive sample such as plasma because the adsorbed sample could be flushed out of the capillary. Besides protein analyses, an efficient analysis of the cationic drugs by capillary electrophoresis/mass spectrometry (CE/MS) was also possible.
通过一种新颖的涂层方法——连续多次离子-聚合物（SMIL）涂层，制备了一种用阳离子聚合物修饰的涂层毛细管。SMIL涂层的实现过程是，首先将阳离子聚合物附着到毛细管内壁，然后将阴离子聚合物附着到阳离子聚合物层，最后将阳离子聚合物附着到阴离子聚合物层。与传统的聚凝胺（PB）修饰毛细管相比，通过SMIL涂层制备的PB修饰毛细管的稳定性显著提高。它在600次重复分析过程中性能稳定，并且对1 M NaOH和0.1 M HCl也表现出很强的稳定性。批间、日间以及毛细管间涂层的相对标准偏差均低于1%，重现性良好。通过SMIL涂层制备的PB修饰毛细管应用于碱性蛋白质分析。即使电解质的pH值接近蛋白质的等电点（pI），它在蛋白质分析中也表现良好。此外，在进样前用0.1 M NaOH冲洗，对于血浆等高吸附性样品能够进行重现性分析，因为吸附的样品可以从毛细管中冲洗出来。除了蛋白质分析外，通过毛细管电泳/质谱联用（CE/MS）对阳离子药物进行高效分析也是可行的。
