title: Dispersive liquid-liquid microextraction for a rapid determination of glyoxal in alcoholic beverages.
abstract: Carbonyl compounds, like glyoxal, methylglyoxal, diacetyl or pentane-2,3-dione, among others, have been widely studied. Besides its endogenous origin, they are originated from foodstuffs and are related to sensorial characteristics in products such as wine and beer. Generally, for their determination, the analytes must be derivatised to adapt them for the detection system and this step takes long time. The main aim of this research was to develop a simultaneous derivatization and extraction method which takes place in only few minutes. 3,4-diaminopyridine, as derivatizing reagent, generate a fluorescent product. This reaction is selective for glyoxal. For this new dispersive liquid-liquid microextraction (DLLME) procedure combined with chromatographic determination of glyoxal, various parameters affecting the extraction were optimized and finally, a mixture of butan-1-ol as dispersant solvent and dichloromethane as extractant solvent were selected. Its chromatographic peak appears at 2.6min. Four Spanish wines and five Spanish beers have been analysed and the results showed that the levels of glyoxal are comprised between 2.8-9.5mgL-1. The proposed DLLME method drastically reduces the reaction time from 2 or 3-20min improving the methods found in the literature. The glyoxal concentration found in the wines and beers analysed do not suppose any health risk.
authors.affiliation: Department of Analytical Chemistry and Research Institute on Water, Climate Change and Sustainability (IACYS), University of Extremadura, 06006 Badajoz, Spain.
authors.forename: María Isabel
authors.initials: MI
authors.lastname: Rodríguez-Cáceres
authors.affiliation: Department of Analytical Chemistry and Research Institute on Water, Climate Change and Sustainability (IACYS), University of Extremadura, 06006 Badajoz, Spain. Electronic address: monicapalominovasco@gmail.com.
authors.forename: Mónica
authors.initials: M
authors.lastname: Palomino-Vasco
authors.affiliation: Department of Analytical Chemistry and Research Institute on Water, Climate Change and Sustainability (IACYS), University of Extremadura, 06006 Badajoz, Spain.
authors.forename: Nielene
authors.initials: N
authors.lastname: Mora-Diez
authors.affiliation: Department of Analytical Chemistry and Research Institute on Water, Climate Change and Sustainability (IACYS), University of Extremadura, 06006 Badajoz, Spain.
authors.forename: María Isabel
authors.initials: MI
authors.lastname: Acedo-Valenzuela
mesh_terms: D001515:Beer / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006037:Glyoxal / Q000032:analysis* / Q000302:isolation & purification*; D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000379:methods*; D014920:Wine / Q000032:analysis*
chemical_list: D006037:Glyoxal
keywords: 3; 4-diaminopyridine; Alcoholic beverages; DLLME; Glyoxal; HPLC-fluorescence