ABSTRACT
The preparation of electrophoretic microcolumn and its application to the electrophoretic separation of amino acids with a 2-mm I.D. fused-silica microcolumn packed with uniform quartz microncrystal prepared by hydrothermal synthesis are reported. With 1.5 mmol/L disodium phosphate buffer solution (pH 11.5) containing 30% (V/V) methanol, the tryptophan, phenylalanine and tyrosine were separated by the microcolumn electrophoresis and detected by an UV spectrophotometer without derivatization. The limits of detection were 0.038, 0.21 and 0.20 mol/L, respectively. The separation efficiency of tryptophan was 4.4×104 plates/m. The sample capacity of the electrophoretic microcolumn achieved 35 μL. The precisions of the microcolumn electrophoresis were satisfactory. The thermal effects of the electrophoretic microcolumn that without packing, packed with 360 μm quartz sand and with 9 μm length quartz microncrystal were discussed, respectively. It was found that the electrophoretic microcolumn packed with quartz microncrystal was able to inhibit Joule heat, increase sample capacity and enhance detection sensitivity. The microcolumn electrophoresis is one of the high-performance separation techniques for an in-situ, real-time and portable electrokinetic flow analysis system.