Yeung K K, Lucy C A
Department of Chemistry, The University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4.
Anal Chem. 1997 Sep 1;69(17):3435-41. doi: 10.1021/ac961231k.
Addition of zwitterionic surfactants such as dodecyldimethyl(3-sulfopropyl)ammonium hydroxide, hexadecyldimethyl(3-sulfopropyl)ammonium hydroxide, and coco (amidopropyl)hydroxyldimethylsulfobetaine (Rewoteric AM CAS U) to an electrophoretic buffer suppress the electroosmotic flow by 50-90%. Onset of suppression occurs at approximately the critical micelle concentration of the surfactant. CAS U effectively suppresses the electroosmotic flow over the pH range 3-12. Addition of 2 mM CAS U to the electrophoretic buffer prevents adsorption of cationic proteins lysozyme, α-chymotrypsinogen A, cytochrome c, and ribonuclease A. Migration time reproducibility for these proteins is ∼1% RSD within 1 day and 2-5% from day to day. Efficiencies in excess of 750 000 plates/m and recoveries of >80% were observed for protein injections from distilled water. Alternatively if 2 mM CAS U is added to samples, recoveries were quantitative, although efficiencies decreased to 325 000-600 000 plates/m. The natural electroosmotic flow of the capillaries is regenerated simply by rinsing with sodium hydroxide.
向电泳缓冲液中添加两性离子表面活性剂，如十二烷基二甲基（3 - 磺丙基）氢氧化铵、十六烷基二甲基（3 - 磺丙基）氢氧化铵和椰油酰胺丙基羟基二甲基磺基甜菜碱（Rewoteric AM CAS U），可使电渗流降低50 - 90%。抑制作用大约在表面活性剂的临界胶束浓度时开始出现。CAS U在pH值3 - 12的范围内能有效抑制电渗流。向电泳缓冲液中添加2 mM的CAS U可防止阳离子蛋白溶菌酶、α - 胰凝乳蛋白酶原A、细胞色素c和核糖核酸酶A的吸附。这些蛋白质的迁移时间重现性在1天内的相对标准偏差约为1%，不同日期之间为2 - 5%。从蒸馏水中进样蛋白质时，观察到柱效超过750000理论塔板数/米，回收率大于80%。另外，如果向样品中添加2 mM的CAS U，回收率是定量的，不过柱效降至325000 - 600000理论塔板数/米。只需用氢氧化钠冲洗即可使毛细管的自然电渗流再生。
