SIMULTANEOUS HIGH-PERFORMANCE CAPILLARY ELECTROPHORESIS ANALYSIS OF THE REDUCED AND OXIDIZED FORMS OF ASCORBATE AND GLUTATHIONE

We describe here a procedure for the simultaneous analysis of the oxid ised and reduced forms of the major cellular hydrophillic antioxidants , ascorbic acid (vitamin C) and glutathione (gamma-L-glutamyl-L-cystei nylglycine), by high-performance capillary electrophoresis. Separation s are performed in uncoated fused-silica capillaries using 200 mmol/l berate pH 9.0, containing 20% (v/v) acetonitrile as the background ele ctrolyte with fixed-wavelength UV absorbance detection at 185 nm. The influence of pH, organic solvent and other additives on the resolution of these compounds is described and we show that the optimised protoc ol is capable of simultaneously resolving other thiol components inclu ding, N-acetylcysteine and methyl-S-glutathione. The method is suitabl e for the analysis of these antioxidants in Arabidopsis and Nicotiana leaf tissue and is compatible with the use of the high ionic strength, acidic extraction solvents which are necessary to quench the redox eq uilibria of these labile components. (C) 1997 Elsevier Science B.V.