title: Selective detection of endogenous thiols using microchip-based flow analysis and mercury/gold amalgam microelectrodes.
abstract: This paper describes the fabrication and characterization of thin-layer mercury/gold amalgam microelectrodes and their integration with microchip-based flow injection analysis. This microchip platform allows on-chip injection and lysis of erythrocytes followed by selective detection of intracellular glutathione (GSH) at low potentials. The thin-layer gold microelectrodes were amalgamated by electrodeposition of mercury. The electrodes produced a linear response for both GSH and cysteine in flow injection analysis studies utilizing both off-chip and on-chip injection. Comparative experiments using diamide and on-chip injection were performed to demonstrate the ability of the microchip device to detect changes in GSH concentration. Finally, rabbit erythrocyte samples (2% hematocrit) were injected and lysed on-chip and the amount of GSH detected corresponded to 312 amol/cell, which is in agreement with previously reported values. The selectivity, short time between injection and detection (approximately 5 s), and the continuous introduction of sample to the on-chip injector should enable the study of dynamically changing systems such as the glutathione redox system found in erythrocytes.
authors.affiliation: Saint Louis University, Department of Chemistry, 3501 Laclede Avenue, St. Louis, MO 63103, USA.
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Batz
authors.forename: R Scott
authors.initials: RS
authors.lastname: Martin
mesh_terms: D000818:Animals; D004912:Erythrocytes / Q000737:chemistry*; D006046:Gold; D008628:Mercury; D046208:Microchip Analytical Procedures / Q000379:methods; D008839:Microelectrodes; D044085:Microfluidics / Q000379:methods; D011817:Rabbits; D013438:Sulfhydryl Compounds / Q000097:blood*
chemical_list: D013438:Sulfhydryl Compounds; D006046:Gold; D008628:Mercury