*2.4. LC-MS*/*MS Analysis*

The analysis was performed using a Shimadzu LCMS-8040 (Kyoto, Japan), with a tandem quadrupole analyzer, in MRM spectrum mode using an electron spray ionization source in both positive and negative ionization modes. The chromatography was performed on a Raptor (Restek Corporation, Bellefonte, PA, USA) biphenyl column (10 cm × 2.1 mm, 2.7 μm-particles) with an adequate guard column, thermostated at 35 ◦C. The mobile phase solvents were 5 mM ammonium formiate in water with 0.1% formic acid and 5 mM ammonium formiate in methanol with 0.1% formic acid. The chromatographic eluting conditions were optimized as follows: from 3% to 10% B (0–1 min), from 10% to 55% B (1–3 min), from 55% to 100% B (3–10.5 min), 100% B maintained for 2.5 min, from 100% to 3% B in 0.01 min), followed by re-equilibration to 3% B for a further 3 min. The total analysis run time was 15 min. The flow rate was 0.4 mL/min and the injection volume was 2 μL. Quantitative and qualitative analyses were performed with LabSolution Insight software based on the two most intensive fragment ion transitions. The matrix matched standards were used for calibration and quantification, prepared by analyzing blank (negative) samples spiked with pesticides after the extraction and purification steps.
