Preparation and Evaluation of Polyvinyl Pyrrolidone-Coated Columns Based on Sol-Gel Chemistry for Capillary Electrophoresis
基于溶胶凝胶技术的聚乙烯吡咯烷酮涂层柱的制备及评价

Polyvinyl pyrrolidone(PVP) coating techniques based on sol-gel chemistry was investigated in this article. Multiple-step coating and single-step coating methods were developed and the coating conditions(molar ratios of MAPS to 0.1 mol/L HCl, reaction times and concentration of PVP) were selected. Electroosmosis mobility and column efficiency were used as the evaluating parameters for coated capillary columns. For multiple-step coating, the optimal sublayer sol solution was obtained by adding 0.1 mol/L hydrochloric acid to MAPS(molar ratio, 1:1) and reacted at room temperature for 2 hours. The best PVP mass concentration was 40 g/L in alcohol. For single-step coating, the sol-gel solution was obtained by mixing the following ingredients: (a)MAPS, (b) 8% PVP alcohol solution and (c) 0.1 mol/L hydrochloric acid in 1:1 molar ratio to MAPS. The mixture was kept at room temperature for 2 hours. Proper amounts of 100 g/L ammonium persulfate and 10% (V/V) N, N, N', N'-tetramethylethylenediamine were then added. The mixture was mixed ultrasonically, then centrifuged at 4,000 r/min for 5 min. The upper clean sol-gel solution was transferred into another clean vial for coating capillary column. The reproducibility of migration times and efficiencies of single-step-coated capillary was better than that of multiple-step-coated capillary. Single-step-coating method was very effective and easy. It can fit the needs in experimental work. Coating techniques based on sol-gel chemistry are prospective but still need to be further developed.