A panel of representative polar pesticides has been targeted in a single liquid chromatographic tandem quadrupole mass spectrometry method, namely aminomethylphosphonic acid (AMPA), chlorate, ethephon, fosetyl aluminium, glufosinate, glyphosate, maleic hydrazide and phosphonic acid. Extracts of various foodstuffs were prepared in accordance with the Quick Polar Pesticides (QuPPe) extraction method. Chromatographic separation was achieved on mixed mode / hydrophilic interaction liquid chromatography (HILIC), applying a mobile phase gradient with neutral pH. Targeted multi-reaction monitoring methods were used, with at least two transitions per compound to quantify and confirm analyte detection.
Chromatographic performance was evaluated in accordance with SANTE guideline document 11954/2015 columns, certain limitations were determined for the challenging analysis of these highly polar pesticides. This evaluation has for a LC-MS/MS method for the direct analysis of anionic pesticides. Retention of all analytes was greater than two times the void volume, while the retention time tolerance for each analyte was within ±0.1 minute of the corresponding matrix matched standard.
Overall method performance, in the absence of isotopically labeled internal standard, was evaluated by assessing linearity, accuracy and sensitivity.