Single run analysis of glutathione and its disulfide in food samples by liquid chromatography coupled to on-line post-column derivatization

Glutathione and its disulfide were determined in a single run using liquid chromatography with on-line postcolumn derivatization and fluorimetric detection (340 nm/425 nm). The analytes were separated using a reversed-phase column capable of operating at 100% aqueous mobile phase and detected following direct on-line reaction with o-phthalaldehyde (7.5 mmol L-1) in highly basic medium (0.37 mol L-1 NaOH). The instrumental and chemical variables were carefully investigated towards high sensitivity and throughput, while special attention was paid to validating potential matrix effects. Glutathione and its disulfide could be selectively determined with respective LODs of 0.10 and 0.30 mu mol L-1 in the absence of matrix effect (<6%). The endogenous content of the analytes was accurately determined in various food samples with recoveries ranging between 80 and 120% in all cases. The proposed method is reliable and promising as a generic analytical tool for the convenient estimation of the redox status of glutathione in various food matrices.

Automated summary

The study successfully developed a method for determining glutathione and its disulfide using liquid chromatography with on-line postcolumn derivatization and fluorimetric detection. The method showed high sensitivity and throughput, with accurate determination of analytes content in various food samples. It is considered a reliable and promising analytical tool for estimating the redox status of glutathione in different food matrices.