High-performance capillary electrophoretic determination of glutathione in human lymphocytes

A high-performance capillary electrophoretic method is described which allows for a sensitive and accurate determination of reduced glutathione (GSH) in human lymphocytes. The method makes use of a fused silica capillary with polyacrylamide coating (total length 27 cm, effective length 20 cm, 75 or 50 mu m i.d.). The detection wavelength is 200 nm. The procedure is very simple: the lymphocyte lysate, after suitable filtration, is diluted 1:1 with pH 7.0 phosphate buffer and Ellman's reagent is subsequently added. This reagent forms a stable adduct with GSH which blocks glutathione into its reduced form and enhances the method sensitivity [limit of detection (LOD) = 5 x 10(-7) M]. Reagent excess does not interfere and thus does not need to be eliminated. The method has the advantage of allowing for a rapid and simultaneous determination of both GSH and its oxidized form, glutathione disulfide (GS,FG), in a complex matrix such as that of human lymphocytes as well as of requiring only small volumes of the sample. (C) 1998 John Wiley & Sons, Inc.