Development of ultra high-resolution capillary liquid phase chromatographic system

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1. Monolithic silica capillary columns dynamically modified with quaternary ammonium ions were evaluated for the determination of bromide in seawater samples. A quaternary ammonium ion such as cetyltrimethylammonium was dynamically introduced onto monolithic silica surfaces. The first layer of the modifier was introduced by electrostatic interaction, whereas the second layer was introduced by hydrophobic interaction. The latter layer worked as the anion-exchange sites. The modified monolithic silica capillary columns could be used for rapid separation of inorganic anions. Separation of authentic mixture of five anions was achieved within a few minutes. The addition of small amount of the modifier in the eluent improved the repeatability of the retention time. Seawater samples could be directly injected onto the prepared capillary columns, and bromide could be determined to be 63 mg/L.2. The application of a boronate precolumn in the trace determination of bisphenol A(4,4'-isopropyliden … More ediphenol or BPA) in aqueous solution was investigated by microcolumn liquid chromatography (LC). BPA was enriched by a precolumn packed with TSKgel boronate and it was then injected (back-flushed) into an ODS separation column. Comparing to a conventional syringe injection, a better peak shape was obtained via the boronate precolumn injection, and the calculated theoretical plate number improvement was approximately 2 folds. The relative standard deviations for the retention time, peak area and peak height were 0.12, 3.0 and 1.8%, respectively. The system is linear (R2 > 0.99) within the working sample concentration and sample-volume ranges, and it presents a detection limit of 0.09μgl^<-1> (S/N=3) when a 0.2 ml sample was enriched. Recovery values of the proposed method were between 107 and 123%, and this method was applied satisfactorily to the determination of BPA in commercially available bottled drink samples. The boronate precolumn was proven to produce better sensitivity than that of an ODS or C30 precolumn as long as the enrichment of BPA in aqueous samples is concerned.3. A novel enzyme-immobilized glass beads based micro column was developed for the on-line, simple and swift protein digestion, followed by peptide separation via reversed-phase HPLC. This inexpensive and easy-made enzyme-immobilized micro column was prepared by using aminopropyl-controlled pore glass that was first reacted with glutaraldehyde followed by reaction with trypsin under the presence of phosphate buffer. Tryptic digestion of bovine serum albumin (BSA) was carried out by simply passing the pre-treated protein solution through the laboratory made trypsin-immobilized column, then followed by separation of tryptic fragments via reversed-phase HPLC. The separation of peptides was found to be equivalent to those done by using a sample which was underwent a conventional enzymatic protein digestion performed in solution. Less