title: Long-chained gemini surfactants for semipermanent wall coatings in capillary electrophoresis of proteins.
abstract: In this paper, we presented the first example of using gemini surfactants as semipermanent coatings in CE for protein separation. These coatings are based on the self-assembly of a series of cationic gemini surfactants, alkanediyl-alpha,omega-bis(dimethylalkylammonium bromide) (m-s-m), on the capillary wall. The coatings can keep stable for a long time without surfactant in the buffer, e.g., after the surfactants were removed from the buffer, the reversed EOF only decreased by 3.6 and 3.9% for 18-2-18 and 16-2-16 coatings over 60 min under continuous electrophoretic conditions. The coating stability increased with the alkyl chain length m. The double long chains of geminis (m > or = 14) yielded a good coating stability; meanwhile, the spacer group acted as an EOF modifier. Thus, this bifunctional surfactant coating provided a new buffer-independent method for EOF control. For 18-s-18 series, the best coating stability and largest EOF were obtained at s = 10. Ranging s from 3 to 10 yielded a linear fine-tuning of EOF and thereby allowed the adjustment of the protein apparent mobility. Highly efficient separation (>500 000 plates/m) was achieved with all the 18-s-18 coatings. Excellent run-to-run and day-to-day reproducibility (RSD of migration time </=0.7 and 4.3% for run-to-run and day-to-day assays, respectively) and fine recoveries (97.5-100.1%) of the protein samples indicated that the gemini semipermanent coatings were quite effective for the wall adsorption suppression of proteins.
authors.affiliation: College of Chemistry & Chemical Engineering, Hunan University, Changsha, P. R. China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Liu
authors.forename: Jinbin
authors.initials: J
authors.lastname: Yuan
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Li
authors.forename: Shouzhuo
authors.initials: S
authors.lastname: Yao
mesh_terms: D019075:Electrophoresis, Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D011506:Proteins / Q000032:analysis*; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D011506:Proteins; D013501:Surface-Active Agents