Novel HPLC - Fluorescence methodology for the determination of methylglyoxal and glyoxal. Application to the analysis of monovarietal wines “Ribera del Guadiana”

The determination and quantification of α-dicarbonyl compounds, glyoxal and methylglyoxal, in “Ribera del Guadiana” monovarietal wines (Extremadura, Spain) without sample clean-up has been carried out by HPLC with spectrofluorimetric detection (307/371 nm). For this purpose, a derivatization step with the new reagent 3,4-diaminopyridine at pH 2 during 120 min at 90 °C has been included. Afterwards, the sample could be injected in the chromatographic system with no clean-up, during a total run time of 4 min. Several monovarietal wines (white, rosé and red) have been analyzed and the levels of these compounds for white wines were between 0.4-1.0 mg L−1 glyoxal and 0.8-1.3 mg L−1 methylglyoxal; and between 0.8-3.0 mg L−1 and 0.5-1.8 mg L−1 of glyoxal and methylglyoxal respectively, in red wines.