Evaluation and validation of an ion mobility quadrupole time-of-flight mass spectrometry pesticide screening approach.

An ion mobility quadrupole time-of-flight mass spectrometry-based pesticide suspect screening methodology was developed and validated covering 20 plant-derived food matrices deriving from six commodity groups of different complexity according to the actual European Commission document SANTE/11813/2017 applying a QuEChERS sample preparation protocol. The method combines ultra-performance liquid chromatography, traveling wave ion mobility, and quadrupole time-of-flight mass spectrometry. Besides the determination of the physicochemical property collision cross-section and the establishment of a corresponding scientific suspect screening database comprising 280 pesticides for several pesticides, different protomers, sodium adducts, as well as dimers were identified in ion mobility spectrometry traces.

Determination of Fosetyl and Phosphonic Acid at 0.010 mg/kg Level by Ion Chromatography Tandem Mass Spectrometry.

A new sensitive, fast, and robust method using ion chromatography tandem mass spectrometry (IC-MS/MS) for the determination of fosetyl and phosphonic acid in plant-derived matrices was developed. For compensation of matrix effects and differences in recovery rates the isotopically labeled internal standard (ILIS) O-labeled phosphonic acid was added to the samples prior to the extraction of the target compounds. The validation of the method for the matrices tomato, apple, lemon, sultana, avocado, and wheat was performed according to the actual EU guidance document SANTE/11945/2015.

Identification and characterization of pesticide metabolites in Brassica species by liquid chromatography travelling wave ion mobility quadrupole time-of-flight mass spectrometry (UPLC-TWIMS-QTOF-MS).

A new mass spectrometric method for evaluating metabolite formation of the pesticides thiacloprid, azoxystrobin, and difenoconazole was developed for the Brassica species pak choi and broccoli. Both, distribution and transformation kinetics of the active compounds and their metabolites were analyzed by UPLC-TWIMS-QTOF-MS. Additionally, HR-MS analysis and structure elucidation tools such as diagnostic ions, isotopic matches, and collision cross sections were applied for metabolites identification.