Fast and simplified quantitative multiresidue analytical method for pesticides in surface waters by UHPLC-MS/MS with online sample preparation.

A quantitative multiresidue analytical method for the simultaneous analysis of current-use agricultural pesticides in surface waters is reported. The method involves minimal sample manipulation and small sample collection volumes (for 1 mL and 5 mL injections) with online sample clean-up and analyte preconcentration on a hydrophilic-lipophilic balance (HLB) column. To our knowledge, this online approach with the use of an HLB column has not yet been reported for multiresidue pesticide analysis in surface waters. Chromatographic separations of isomeric pesticides were achieved through the sequential coupling of C8 and polar endcapped C18 analytical columns. High resolution accurate mass (HRAM) quadrupole Orbitrap spectrometry was performed in full scan mode followed by data-dependent MS/MS fragmentation (FS-ddMS2) with concurrent electrospray ionization in both positive and negative modes. The method was validated for thirty-one (31) diverse current-use pesticides and demonstrated strong linearity (R2 > 0.9912) and precision (% RSD <8.4%) with low quantitation limits (average LOQ of 41 ng L-1). The majority of target analytes experienced minimal matrix effects (<±20%) in fortified environmental water samples. When applied to surface water samples, the method detected fourteen of the target analytes, including twelve herbicides, one insecticide, and one fungicide. This method offers a fast, simple, and reliable approach for the quantitative analysis of diverse current-use pesticides in surface water samples within hours of sample collection in the field. The robust nature of the method may allow for potential application to other types of water and the targeted or untargeted screening of other emerging contaminants.