Multiplexed analysis of 215 pesticides triggering by Scout-MRM method

LC-MS-MS combined with Selected Reaction Monitoring (SRM) mode is a gold standard method to analyze pesticides. While the number of targets increases, specific analyte transitions are monitored around their expected retention time (RT) in order to ensure correct definition of peak shape. In this context, large RT window is applied during the analysis in contrast to large peak width and to take in account any RT drift. However, any additional or even minor modification of the LC configuration (extra-column volume change, flow rate, column length or diameter…) requires adjustment of this RT window. Because of independency towards RT, the new scout-MRM software alleviates all these limitations and expands the multiplexing capability as illustrated by multi-residue analysis of 215 pesticides. In the context of multi-residue pesticide assay, this preliminary study focused on a new scout-MRM software towards other multiplexed monitoring modes in term of repeatability and accuracy. Scout signals are displayed by 5 spiked deuterated pesticides triggering 5 groups of transitions (2 transitions per pesticide, 430 transitions in total). Repeatability of scout-MRM and scheduled-MRM methods were assessed by calculating CVs from triplicate analysis from 174 pesticides standard mix. Average CVs is about 3% for both methods, showing equivalent performances. Finally, scout-MRM was used for multi-residue screening and quantification of pesticides in surface water samples by applying an external calibration procedure. Accuracy of scout-MRM quantification results was ultimately compared to ones obtained with conventional scheduled-MRMTM method.