In-solution derivatization and detection of glyoxal and methylglyoxal in alcoholic beverages and fermented foods by headspace solid-phase microextraction and gas chromatography–mass spectrometry

Abstract

A simple and sensitive method for the simultaneous determination of glyoxal and methylglyoxal in alcoholic beverages and fermented foods was developed. This method involved simultaneous derivatization in solution with 2,2,2-trifluoroethyl hydrazine (TFEH) and headspace solid phase microextraction, followed by detection via gas chromatography-mass spectrometry (GC–MS). The method established herein can be summarized as follows. The sample was adjusted to pH 6.0 in a headspace vial, saturated with sodium chloride, and allowed to react with TFEH at 85 °C for 20 min. The formed derivatives were vaporized and adsorbed on divinylbenzene/carboxy/polydimethylsiloxane fibers. The TFEH derivatives were subsequently desorbed and analyzed by GC–MS, where the spectrum showed a single sharp peak. Under the established conditions, the quantification limits of glyoxal and methylglyoxal were 3.6 and 2.1 μg kg−1, respectively, and the relative standard deviations were under 8% at concentrations of 20, 100 and 2000 μg kg−1. All samples were detectable at typical glyoxal (62–4116 μg kg−1) and methylglyoxal (11–2342 μg kg−1) concentrations in beverages and foods.