Determination of organophosphate pesticides in sea and surface water with ultrasound-assisted dispersive liquid–liquid micro-extraction coupled to GC-MS/MS analysis

<p>A sensitive enrichment method for the detection and quantification of 20 organophosphate pesticides in sea water and surface water was improved and validated. The compounds were extracted using ultrasound-assisted dispersive liquid–liquid microextraction and were analysed with an optimised Gas Chromatography - Tandem Quadrupole Mass Spectrometry (GC-MS/MS) method. Calibrations and validations were conducted for spiked local pond and Baltic Sea water. Recoveries of the organophosphate compounds from the different matrices ranged from about 25% to 70% and from 30% to 130% for pond and sea water, respectively. Obtained limit of detection (LoD) for both matrices was about 3 ng L<sup>−1</sup> and the limit of quantification (<i>k</i> = 3) was 12 and 7 ng L<sup>−1</sup> for pond and sea water, respectively. Valid extractability at the LoD level could be proven.</p>