Gas chromatographic ion trap mass spectrometry determination of zoxamide residues in grape, grape processing, and in the fermentation process

A gas chromatographic ion-trap mass spectrometry (GC-ITMS) method was developed for the determination of the fungicide zoxamide in grape, must, wine, and spirits. Samples were extracted with hexane and analyzed without any clean up. The gas chromatograph was fitted with a carbofrit inserted into the glass liner to allow large volume injections. Analyses were carried out both in EI and CI mode. Recoveries from fortified samples ranged between 86 and 114% at four different fortification levels (n = 6 each), ranging between 0.05 and 2.00 mg/kg. The relative standard deviation was below 19%. Both in EI and CI mode the calculated limit of detection (LOD) and quantification (LOQ) were 0.01 and 0.05 mg/kg (0.08 mg/kg in CI), respectively. Moreover the influence of yeasts and bacteria fermentation was evaluated.