title: Micromachined separation chips with a precolumn reactor and end-column electrochemical detector.
abstract: Glass microchips, integrating chemical derivatization reactions, electrophoretic separations, and amperometric detection, have been developed. The performance of the new integrated microfabricated devices is demonstrated for rapid on-chip measurements of amino acids utilizing precolumn reactions of amino acids with o-phthaldialdehyde/2-mercaptoethanol to generate electroactive derivatives that are separated electrophoretically and detected at the end-column electrochemical detector. The influence of the sample/reagent mixing ratio, reagent concentrations, driving voltage, detection potential, and other variables is explored. The integrated microsystem offers a rapid (6 min) simultaneous measurements of eight amino acids, down to approximately 2.5 x 10(-6) M (5 fmol) level, with linearity up to the 2 x 10(-4) M level examined, and good reproducibility (RSD = 2.2-2.7%). A step of the driving voltage is used for decreasing the migration time of late-eluting components and reducing the overall analysis time. The integrated microfabricated device expands the scope of on-chip electrochemical detection to nonelectroactive analytes and holds promise of being a powerful analytical tool.
authors: Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces 88003, USA.
authors: J
authors: J
authors: Wang
authors: M P
authors: MP
authors: Chatrathi
authors: B
authors: B
authors: Tian
mesh_terms: D004563:Electrochemistry / Q000295:instrumentation*; D004586:Electrophoresis / Q000295:instrumentation; D007202:Indicators and Reagents; D008904:Miniaturization
chemical_list: D007202:Indicators and Reagents