Zwitterionic hydrophilic interaction chromatography coupled with post-column derivatization for the analysis of glutathione in wine samples

• One of the very first combinations of HILIC with post-column derivatization.
• GSH is determined at the low micromolar level in wines without matrix effect.
• Excess of sulfite preservation reagent does not affect the analysis.

In this study the development, validation and application of a new chromatographic method for the determination of glutathione (GSH) in wine samples is presented. The separation of the GSH was carried out using a sulfobetaine-based hydrophilic interaction chromatography (HILIC) analytical column whereas its detection was carried out spectrofluorimetrically (λext/λem = 340/455 nm) after post-column derivatization with o-phthalaldehyde. GSH was separated efficiently from matrix endogenous compounds of wines by using a mobile phase of 15 mmol L−1 CH3COONH4 (pH = 2.5)/CH3CN, 35/65% (v/v). The parameters of the post-column reaction (pH, amount concentration of the reagent and buffer solution, flow rate, length of the reaction coil) were investigated. The linear determination range for GSH was 0.25–5.0 μmol L−1 and the LOD was 19 nmol L−1. No matrix effect was observed, while the accuracy was evaluated with recovery experiments and was ranged between 89% and 108%.

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