title: Applications of LC/ESI-MS/MS and UHPLC QqTOF  MS for the determination of 148 pesticides in fruits  and vegetables.
abstract: This paper presented the applications of liquid chromatography electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) and ultra-high-pressure liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry (UHPLC QqTOF MS) for the determination of 148 pesticides in fruits and vegetables. Pesticides were extracted from fruits and vegetables using a buffered QuEChERS method. Quantification was achieved using matrix-matched standard calibration curves with isotopically labeled standards or a chemical analog as internal standards in an analytical range from 5 to 500 microg/kg. The method performance parameters including overall recovery, intermediate precision, and measurement uncertainty were evaluated according to a statistically designed experiment, i.e., a nested design. For LC/ESI-MS/MS, 95% of the pesticides had recoveries between 81% and 110%; 97% had an intermediate precision < or = 20%; and 95% (in fruits) or 93% (in vegetables) showed measurement uncertainty < or = 40%. Compared to LC/ESI-MS/MS, UHPLC QqTOF MS showed a relatively poor repeatability and large measurement uncertainty. About 93% (in fruits) or 94% (in vegetables) of the pesticides had recoveries between 81% and 110%; 86% (in fruits) or 90% (in vegetables) had an intermediate precision < or = 20%; and 79% (in fruits) or 88% (in vegetables) showed measurement uncertainty < or = 40%. LC/ESI-MS/MS proved to be the first choice for quantification or pre-target analysis due to its superior sensitivity and good repeatability. UHPLC QqTOF MS provided accurate mass measurement and isotopic patterns, and was an ideal tool for post-target screening and confirmation.
authors.affiliation: Calgary Laboratory, Canadian Food Inspection Agency, 3650-36th Street N.W, Calgary, AB T2L 2L1, Canada. Jian.Wang@inspection.gc.ca
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Willis
authors.initials: W
authors.lastname: Chow
authors.forename: Daniel
authors.initials: D
authors.lastname: Leung
mesh_terms: D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D005506:Food Contamination / Q000032:analysis; D005524:Food Technology / Q000379:methods*; D005638:Fruit / Q000737:chemistry*; D015394:Molecular Structure; D010575:Pesticides / Q000032:analysis*; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization; D014675:Vegetables / Q000737:chemistry*
chemical_list: D010575:Pesticides