Simultaneous determination of glutathione and glutathione disulfide in an acid extract of plant shoot and root by Capillary Electrophoresis

Abstract

This study describes the fast and simultaneous determination of glutathione and glutathione disulfide by Capillary Zone Electrophoresis in plant extracts of shoot and root of tomato plants. Frequent use of acidic precipitation of protein generates an acidic matrix of strength and pH that may cause changes in the method sensitivity, comigration of species or changes in the equilibria that relate both species in cells or fluids. In this study, the resulting acidic matrix was previously treated with the same background electrolyte to prevent comigration and to improve signal resolution. Optimization of some parameters of the technique allowed the determination of both analytes in less than three minutes. The optimized method showed good reproducibility and linearity, with correlation coefficients above 0.999 and detection limits below 3 μM for both peptides. Analyte recovery in the process was in the 88-104% range. The concentration found in tomato plants hydroponically grown in the absence of stress factors was in the 51-100 nmol g-1 range, fresh weight for GSH and 5-32 nmol g-1 range, fresh weight for GSSG.