Application of ultra performance liquid chromatography–tandem mass spectrometry to the analysis of priority pesticides in groundwater

Ultra performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry (UPLC™-MS/MS) has been applied for the accurate and rapid analysis of nine trace level priority pesticides in water. The UPLC™ technology, based on the use of columns packed with 1.7 μm porous particles combined with higher pressures than those conventionally applied in HPLC, enabled to improve in peak resolution, sensitivity and speed of analysis. UPLC™ chromatograms showed very sharp peaks with less than 2 s wide at the base, except for alachlor. This enhanced efficiency resulted in an increased separation speed of the whole UPLC™-MS/MS procedure that required less than 5 min. Limits of detection, determined for 300 ml water samples after SPE preconcentration were in the range between 0.1 and 20 ng/L. The presence of matrix effects or ion suppression was checked by the obtaining of calibration curves in both pure solvent and matrix matched standards. Other performance characteristics of the method, such as linearity and precision were also satisfactory. Finally, the method was successfully applied to the analysis of two water samples from an inter-laboratory exercise.