Agilent Technologies has produced an application note describing the use of a novel high-resolution, low-energy EI-capable GC/Q-TOF to screen pesticides and other contaminants in food matrices.
The increasing demand of screening for contaminants in food requires an efficient and sensitive technique. High-resolution GC/Q-TOF has emerged as a tool to fit this purpose for GC-amenable compounds. The same full-spectrum accurate mass data enable both the confident identification of compounds in the sample and quantitation capabilities to address stringent maximum residue level (MRL) requirements. The addition of low-energy electron impact (EI) ionization enhances the possibility to preserve or confirm molecular ions in EI mass spectra, aiding in the study of unknowns.
Homogenized food commodities were extracted using a QuEChERS (EN) kit. The cleanup of avocado extract used EMR—Lipid dSPE and drying pouches. Broccoli extract was cleaned up by dSPE for pigment matrix and others by dSPE for fruits/vegetables. To evaluate the method, a mixture of 140+ pesticides was spiked into the organic matrices. Screening of contaminants was performed on nonorganic food extracts.
A retention-time-locked method was set up to acquire data using an Agilent 7250 GC/Q-TOF system configured with a mid-column backflushing system.
For data processing, Agilent MassHunter Data Analysis Software B.08.00, including SureMass, was used. The targeted screening of pesticides (a combined quantitative and qualitative workflow) was based on a commercial GC/Q-TOF pesticides library, which contains accurate mass spectra and retention times for 850+ compounds.
- An Agilent 7250 GC/Q-TOF was used successfully to screen pesticides in various food matrices.
- Confidence in results is enhanced by stable RT, repeatable response, and good mass accuracy.
- A wide linear response range was achieved for matrix‑matched calibration.
- Low-energy EI facilitates untargeted screening.