Quantification of glutathione in plasma samples by HPLC using 4-fluoro-7-nitrobenzofurazan as a fluorescent labeling reagent.

A rapid and highly sensitive high-performance liquid chromatograpy method with fluorescence detection has been developed for determination of glutathione (GSH) in human plasma. A simple pre-column derivatization procedure with 7-flouro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-F) reagent was employed. The separation of the derivatized glutathione was performed using a mobile phase consisting of phosphate buffer (0.02 mol/L, pH 6.0)-acetonitrile (77:23, v/v) at a flow rate of 1.0 mL/min with the column temperature 2°C. The eluted derivatives were fluorometrically detected at an excitation wavelength 470 nm and an emission wavelength 530 nm. Under the optimum chromatographic conditions, the calibration curve was linear over the range of 0.1 µmol/L to 10.0 µmol/L with the correlation coefficient of 0.9988. The precision of the method was satisfactory with the intra- and inter-day coefficient of variation being 6.3%, 6.9%, respectively. This method has been used to determine glutathione concentrations in plasma samples from healthy individuals.