In this work, a method for multiclass determination of 70 pesticides residues with different properties in drinking water using solid phase extraction (SPE) with polymeric sorbent and determination by gas and liquid chromatography coupled to tandem mass spectrometry (GC-MS/MS and LC-MS/MS) was developed and validated. Different sample volumes, sorbents and elution solvents were evaluated. The best results were obtained using the sorbent Oasis® HLB, sample acidified at pH 2.5 and a mixture of dichloromethane/methanol as eluent. The limit of quantification (LOD) of the method was 0.02 µg L-1 for aldrin, dieldrin and chlordane and 0.5 µg L-1 for the other compounds. Satisfactory accuracy, with recoveries between 70 and 117.3%, and good precision, with relative standard deviation (RSD) values below 19.7% for most of the compounds, were achieved. The validated method was applied to real water samples and results indicated that the proposed method is suitable for the determination of pesticide residues in water samples.

Considering the possibility that pesticides used in cattle raising produce residues in milk and cause harm to public health, this study developed a multiresidue method for determination of pesticide residues in bovine milk, using a modified QuEChERS method for sample preparation, and quantification by GC-MS/MS. The method proved to be efficient, resulting in satisfactory recoveries in the range 71.1 to 117.4%, for 45 of the 48 compounds analyzed with RSD values < 17.3%. The method LOD and LOQ were3.0 and 10.0 µg L-1, respectively, except for cyfluthrin which showed 7.5 and 25.0 µg L-1.

The determination of veterinary drug residues in foods of animal origin is an important issue because of the risk these compounds pose to human health in addition to their persistence and tendency to bioaccumulate. In recent years, significant progress has been made in the area and this review presents the state of the art in sample preparation procedures associated with chromatographic techniques coupled to mass spectrometry for multiresidue determination of veterinary drugs in food of animal origin at concentration levels suitable for the control of residues and contaminants in food.