Recent advances on the use of liquid chromatography-high resolution mass spectrometry (LC-HRMS) have shown its capabilities and applications in broad-spectrum screening or “discovery” analysis to allow for the determination of chemical compounds and for compounds that are unexpected or to have a low frequency of presence in the sample.  HRMS provides accurate masses, which are essential for the assignment of the elemental composition and molecular formula of a particular compound.  Proposed structural assignments of precursor and product ions based on the molecular formula will also support the identification of chemical contaminants in complex matrices, including food and feed.  HR MS/MS spectra of pesticides, mycotoxins, and veterinary drugs were acquired using liquid chromatography coupled to a quadrupole-Orbitrap mass spectrometer operated in positive electrospray ionization mode with full scan and data-dependent MS/MS acquisition.  A MS/MS library was developed for over 1000 pesticides (and metabolites), 50 mycotoxins, and 200 veterinary drugs based on the calculated monoisotopic exact masses of the ions.  Software algorithms and a compound database based on the MS/MS libraries were used to automatically screen the spectra collected from food matrices for residues and contaminants prepared from generic sample preparation procedures (QuEChERS, dilute-and-shoot) and LC-HR-MS/MS approaches (i.e., data-dependent acquisition, all-ion fragmentation, data-independent acquisition).  The use of the MS/MS libraries will also be helpful in selecting MS/MS product ion transitions for targeted LC-MS/MS method development using a triple quadrupole instrument.  Finally, the practical use of HR MS/MS spectra is demonstrated to support the assignment of fragmentation patterns from previously published low resolution MS/MS studies.<br/>

Development and use of UHPLC-HRMS, MS/MS libraries, and compound databases for screening chemical residues and contaminants in foods

254th National Meeting (2017)

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