[Uncharged monolithic capillary column modified with an anionic surfactant in electrochromatography].

A monolithic capillary column was obtained by in-situ co-polymerization of butyl methacrylate with ethylene dimethacrylate. A mode of capillary electrochromatography (CEC) based on the dynamic adsorption of long chain sodium dodecyl sulfate(SDS) on the monolithic stationary phases was developed. Effects of SDS concentration and concentration of acetonitrile in mobile phase on the electroosmotic flow(EOF) of the column and the plate height on the electroosmotic velocity were investigated. Efficiency of monolithic capillary column with higher than 140,000 plates per meter for neutral aromatic compounds were obtained, and the relative standard deviations observed for dead time(t0) and retention times of neutral solutes were about 0.22% and less than 0.56% for ten consecutive runs, respectively.

[Chiral separation by capillary electrochromatography on stationary phase adsorbed with protein].

A method based on the adsorption of bovine serum albumin (BSA) on the strong anion-exchange packing (SAX) was applied to prepare chiral stationary phases for capillary electrochromatography. It was found that the electroosmotic mobility only decreased 26.3% when the BSA was adsorbed. The run-to-run reproducibilities of void time and the migration times of D- and L-tryptophan enantiomers were rather good with the relative standard deviation (RSD) values of 0.90%, 0.87% and 0.96%, respectively, when mobile phase containing 7% (volume fraction) acetonitrile. The merit of this system is that the direction of electroosmotic flow is still from cathode to anode, preferable to separate acidic enantiomers. Four anionic enantiomers, tryptophan, ketoprofen, fenoprofen and warfarin, as well as the neutral enantiomers of benzoin were successfully resolved. In order to reduce the analysis time, n-hexanoic acid was added to the mobile phase as a competitive agent. The effect of acetonitrile volume fraction on the resolution of enantiomers was also investigated.

[The preliminary study on the open tubular capillary affinity liquid chromatography].

A novel mode of affinity chromatography based on the open tubular column (OTAC) is presented in this paper. The OTAC column was prepared by coating a layer of Cibacron Blue F3GA onto the inner surface of capillary column with 50 microns inner diameter. The affinity chromatography experiment was performed on a capillary electrophoresis instrument by using its pressure system as driving force. The bovine serum albumin (BSA) and lysozyme (Lys) were successfully separated with step gradient elution. The relative standard deviation (RSD) for 10 consecutive runs for the elution time of lysozyme was less than 0.1%, and those for its peak area and peak height were 4.3% and 3.7% respectively. The good linear relationships of the amount of the injected lysozyme versus its peak area and peak height were observed with correlation coefficients of 0.9946 and 0.9988 respectively in the range from 8.6 ng to 28.7 ng.