UHPLC/ESI Q-Orbitrap Quantitation of 655 Pesticide Residues in Fruits and Vegetables-A Companion to an nDATA Working Flow.

Background: Effective and expansive methods for multiresidue pesticide analysis are desired for routine monitoring programs. These methods are complex, especially when several hundred pesticides are involved. Objective: Two approaches to sort data and identify isomers and isobaric ions in pesticide mixtures were evaluated to determine whether they could be differentiated by mass resolving power and/or chromatographic resolution. Method: This study presents an application of ultra-high performance liquid chromatography electrospray Q-Orbitrap mass spectrometry (UHPLC/ESI Q-Orbitrap) along with QuEChERS for the quantitation of 655 pesticide residues in fruits and vegetables. Results: From the developed method, 94.7% of the 655 pesticides in fruits and 93.9% of those in vegetables had recoveries between 81% and 110%; 98.3% in both fruits and vegetables had an intermediate precision of <= 20%; and 97.7% in fruits or 97.4% in vegetables showed measurement uncertainty of <= 50%. When the retention time difference (Delta t(R)) of two isomers was >= 0.12 min, they were chromatographically resolved. Twenty five out of 35 pairs or groups of isomers were chromatographically separated (Delta t(R) >= 0.12 min), but 14 pairs were not resolved (Delta t(R) < 0.12 min). There were 493 pairs of pesticides with a mass-to-charge difference of <1 Da. Only one pair of isobaric ions could not be separated by mass and chromatographic resolution. Highlights: UHPLC/ESI Q-Orbitrap along with QuEChERS sample preparation offers a practical quantitative companion method to a non-target data acquisition for target analysis workflow for pesticide residue analysis in routine monitoring programs for food safety.