DETERMINATION OF GLUTATHIONE AND RELATED AMINOTHIOLS BY GAS-CHROMATOGRAPHY WITH FLAME PHOTOMETRIC DETECTION

A selective and sensitive method for the determination of glutathione (GSH) and related aminothiols such as cysteine (Cys), cysteinylglycine (CysGly) and gamma-glutamylcysteine (gamma-GluCys) by gas chromatogra phy (GC) has been developed. GSH and related aminothiols were converte d into their N,S-isopropoxycarbonyl methyl ester derivatives and measu red by GC with flame photometric detection using a short capillary col umn (5 m X 0.53 mm i.d.) of cross-linked DB-1. The calibration curves were linear in the range 1-25 nmol for GSH and in the range 0.2-5 nmol for other aminothiols, and the detection limits of GSH, Cys, CysGly a nd gamma-GluCys were approximately 5, 0.2, 0.3 and 0.5 pmol per inject ion respectively. This method was successfully applied to blood sample s without prior clean-up, and GSH and related aminothiols in these sam ples could be analysed without any influence from coexisting substance s. Overall recoveries of GSH and other aminothiols added to blood samp les were 88-107%. The analytical results of free and total blood GSH a nd related aminothiols in normal subjects are presented.