Packed capillary liquid chromatography coupled to fluorescence detection: application to human blood samples for the determination of glutathione.

The present investigation analyses the potentials of capillary chromatography using packed fused silica capillaries filled with 5 microns RP-18 for the fluorescence determination of glutathione in human blood samples. Adaptation of conventional HPLC equipment for miniaturized chromatographic assays proved successful. Sample preparation was relatively simple, though care should be taken in sample handling. The thiolic compound mercaptoethanol was used as internal standard. Qualitative determinations were based on standard addition providing increased peak heights at identical retention times. Quantitative determinations gave linear calibration curves, with a standard glutathione recovery of 98.9% and an intra-assay reproducibility of 3.3%. The glutathione values measured appeared within the normal range of 0.9-1.7 mmol glutathione per litre of blood.