Applications of LC/ESI-MS/MS and UHPLC QqTOF MS for the Determination of 148 Pesticides in Berries

Applications of liquid chromatography electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) and ultrahigh-pressure liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry (UHPLC QqTOF MS) for the determination of 148 pesticides in berry fruits are presented in this study. Pesticides were extracted from berries using a procedure known as QuEChERS (quick, easy, cheap, effective, rugged, and safe). Quantification, with an analytical range from 5 to 500 mu g/kg, was achieved using matrix-matched standard calibration curves with isotopically labeled standards or a chemical analogue as internal standards. The method performance parameters, which included overall recovery, intermediate precision, and measurement uncertainty, were evaluated according to a designed experiment, that is, the nested design. For LC/ESI-MS/MS, 95% of the pesticides studied had recoveries between 81 and 110%, 98% of the pesticides had intermediate precision of <= 20%, and 95% of the pesticides showed measurement uncertainty of <= 40%. Compared to LC/ESI-MS/MS, UHPLC QqTOF MS showed a relatively poor repeatability and large measurement uncertainty. Ninety-five percent of the pesticides analyzed by UHPLC QqTOF MS had recoveries between 81 and 110%, 86% of the pesticides had intermediate precision of <= 20%, and 83% of the pesticides showed measurement uncertainty of <= 40%. LC/ESI-MS/MS proved to be the first choice for quantification or pretarget analysis due to its superior sensitivity and good repeatability. UHPLC QqTOF MS provided accurate mass measurement and was an ideal tool for post-target screening and confirmation.