Determination of pesticides in water samples by solid phase extraction and gas chromatography tandem mass spectrometry

A multiresidue method for the determination of more than 80 pesticides in water has been developed and validated. The proposed method is based on SPE followed by GC coupled to MS/MS. Different variables affecting SPE procedure, such as cartridges, sample volume and solvents were studied, and mass spectrometric conditions were optimised in order to increase selectivity and sensitivity. Calibration curves were linear over the range of 0.03-0.5 mu g/L. Recoveries were in the range of 70-110% and repeatability was below 20% for the lowest calibration point. LODs ranged from 0.001 to 0.025 mu g/L and LOQs from 0.003 to 0.076 mu g/L. Finally, the method was successfully applied to the analysis of water samples from southeast of Spain.