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An effective method for pesticide residues determination in tobacco by GC-MS/MS and UHPLC-MS/MS employing acetonitrile extraction with low-temperature precipitation and d-SPE clean-up

Bernardi, Gabrieli, Kemmerich, Magali, Ribeiro, Lucila C., Adaime, Martha B., Zanella, Renato, Prestes, Osmar D.
Talanta 2016 v.161 pp. 40-47
acetonitrile, gas chromatography, isofenphos, pesticide residues, solid phase extraction, statistical analysis, tandem mass spectrometry, tobacco, ultra-performance liquid chromatography
An effective method has been developed and validated for the determination of residues of 55 pesticides in tobacco. The proposed sample preparation method is based on acetonitrile extraction, low-temperature precipitation (LTP) and dispersive solid phase extraction (d-SPE) clean-up. Gas chromatography and ultra-high performance liquid chromatography analysis, both coupled to tandem mass spectrometry (GC-MS/MS and UHPLC-MS/MS), were used for determination. LTP is easy to perform and was crucial to obtain a clean extract. Method quantification limit for the pesticides were between 25 and 75µgkg−1. Extraction recoveries obtained for blank samples spiked at 25, 75, 125 and 250µgkg−1 levels ranged from 63 to 161% with relative standard deviations (RSD)≤20%. The method was successfully applied to the analysis of thirteen different tobacco samples, providing to be a robust procedure for routine analysis. The compounds pirimiphos methyl and isofenphos presented residues in the range of 35–51µgkg−1.