DEVELOPMENT AND VALIDATION OF A DISPERSIVE SOLID PHASE EXTRACTION LIQUID CHROMATOGRAPHY MASS SPECTROMETRY METHOD WITH ELECTROSPRAY IONIZATION FOR THE DETERMINATION OF MULTICLASS PESTICIDES AND METABOLITES IN MEAT AND MILK

A dispersive solid phase extraction-liquid chromatography tandem mass spectrometry method with electrospray ionization was validated in food of animal origin for the determination of multiclass pesticide residues and their metabolites. A simple and low-cost sample preparation procedure using freezing as the clean-up step was used to identify and quantify analytes belonging to 39 different chemical classes in meat and milk matrices. Mean recoveries in the range of 70-120% with relative standard deviations <10% were obtained for the majority of the analytes. The limit of quantification of the method was 10 mu g/kg. The matrix effects were statistically evaluated and the quantification of the analytes was conducted using calibration curves constructed with matrix matched calibration standards covering concentrations from 5 to 200 mu g/kg. The proposed method was applied in 86 samples of animal origin taken from the Greek market, two of which were found positive for pesticides.