Determination of organophosphorus pesticides in surface water by gas chromatography coupled to tandem mass spectrometry

Treball final de Grau en Química. Codi: QU0943. Curs acadèmic 2015-2016An analytical method has been developed for the simultaneous quantification and determination of organophosphorus pesticides in surface water by gas chromatography coupled to mass spectrometry with a triple quadrupole analyzer. The study has been focused on the determination of three insecticides of the same chemical family. In this work, a solid phase extraction was performed using Oasis HLB PRiME cartridges and an isotopically-labeled internal standard was added before extraction as surrogate. Analyses were performed by gas chromatography with tandem mass spectrometry (MS/MS) in electron ionization mode, and three MS/MS transitions were acquired for each analyte, using q/Q ratio as a confirmatory parameter. The method was validated at two levels: 0.15 μg L-1 and 0.75 μg L-1. The recoveries obtained were between 70-120% and the relative standard deviations were lower than 20%. Once the method was validated, it was applied to the analysis of surface water collected from Castellón (Spain) and no positive findings were obtained