Rapid analysis of fungicides in white wines from Northwest Spain by ultrasound-assisted emulsification-microextraction and gas chromatography-mass spectrometry
A rapid, efficient and low-cost method based on ultrasound-assisted emulsification-microextraction (USAEME) and gas chromatography-mass spectrometry was developed for the analysis of several fungicides, belonging to different chemical families, in white wines. The experimental procedure was optimized using factorial design to study the influence of the solvent type, extraction time, extraction temperature, sample, pH, and salt addition on the extraction efficiency. Under the selected conditions, compounds were extracted into 200 μL chloroform from 10 mL of wine sample in only 5 min at ambient temperature. The method was validated using real wine samples, with fungicide recoveries generally ranging from 70 to 115%, good intra- and inter-day precision (relative standard deviation (RSD) values ≤12%), and limits of detection at the sub-ng per millilitre level (LOD ≤ 0.1 ng mL−1). The application of the method to varietal wines belonging to different brands showed the presence of fungicides in all samples at concentrations ranging from 1 to 700 ng mL−1, with a minimum of two and a maximum of seven chemicals per sample.