Solid-phase microextraction for the gas chromatography mass spectrometric determination of oxazole fungicides in malt beverages

This paper describes a method for the sensitive, selective, and solvent-free determination of six oxazole fungicide residues (hymexazol, drazoxolon, vinclozolin, chlozolinate, oxadixyl, and famoxadone) in malt beverages. Direct immersion solid-phase microextraction (DI-SPME) coupled to gas chromatography with mass spectrometry in the selected ion monitoring mode, GC-MS(SIM), is used. A comparison of the optimal fiber used, a polar carbowax–divinylbenzene 70-μm fiber, and a nonpolar polydimethylsiloxane 100-μm fiber was carried out. Optimal extraction conditions were 60 °C and an extraction time of 30 min under continuous stirring. Desorption was carried out at 250 °C for 5 min. Detection limits ranged from 0.006 to 0.3 μg L−1 at a signal to noise ratio of 3, depending on the compound. The proposed method was successfully applied to malt beverages including malt, beer, and whisky, and none of the samples contained residues higher than detection limits.