This paper describes the use of the AB SCIEX TripleTOF 5600 LC–MS–MS system for targeted and non-targeted screening for pesticide residue in food samples. High resolution and accurate mass MS information was used to quantify compounds and MS–MS spectra were used to identify compounds based on mass spectral library searching.
Fruit and vegetable samples were extracted using a QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) procedure.1,2 Extracts were diluted 10× to minimize possible matrix effects. UHPLC separation was achieved using a Shimadzu UFLCXR system with a Restek Ultra II Aqueous C18 2.2 µm (100 × 2.1 mm) column and a gradient of water and methanol with ammonium formate buffer. The AB SCIEX TripleTOF 5600 LC–MS–MS equipped with Turbo V source and electrospray ionization (ESI) probe was used. Full scan MS spectra were acquired over a mass range of 100–1000 Da with an accumulation time of 100 ms. Information dependent acquisition (IDA) was used to collect up to 30 MS–MS spectra with an accumulation time of 25 ms for compound identification based on mass spectral library search. Collision energy settings were standardized to acquire library spectra and data of unknown samples: collision energy (CE) = 35 V with collision energy spread (CES) = ±15 V.Results and Discussion
A catalogue of accurate mass molecular ions was generated containing the information of ~1700 pesticides from an on-line database to screen for pesticides in food samples.3
The new AB SCIEX TripleTOF 5600 LC–MS–MS system was used to screen for, quantify and identify pesticide residues in food extracts. High sensitivity of detection allowed dilution of QuEChERS extracts to minimize possible matrix effects. Accurate mass MS–MS spectra were searched against an existing LC–MS–MS library of pesticides to confirm the identity of quantified analytes.
1. M. Anastassiades et al., J. AOAC Int., 86, 412–431 (2003).
2. EN 15662:2007: (2007).
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