Multi-residue screening and confirmation of pesticides in complex matrices by LC-MS/MS with new triggered MRM acquisition and spectral library comparison

摘要

False positive identifications of pesticides in food products are a major concern for official control labs, often affiliated with tremendous economic damage. It was shown that several pesticide-matrix combinations exist for which false positive identifications could occur if only 2 MRM transitions are acquired. Triggered MRM in combination with library searching against a reference spectra library reliably eliminates false positives. Due to the use of optimized collision energies for each MRM and due to reasonably long dwell times per transition, tMRM is more sensitive and results in more reproducible spectra compared to data dependent product ion scans. Linear calibration curves and excellent precision data for replicate injections show that quantitation is not compromised when triggering additional transitions for confirmation.