Determination of 39 Organophosphorus Pesticides in Tea by Online Gel Permeation Chromatography-Gas Chromatography Tandem Mass Spectrometry Coupled with Modified QuEChERS Method
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Graphical Abstract
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Abstract
The tea sample of 4.000 0 g, acetonitrile of 10.0 mL and 4.00 mg·L-1 heptachlor epoxide internal standard solution of 400 μL were swirled for 1 min, and extracted ultrasonically for 15 min. After centrifugation, the supernatant of 1.0 mL was taken and toluene of 1 mL was added. The mixture was purified with dispersive solid phase extraction adsorbents containing PSA of 30 mg, C18 of 30 mg, GCB of 15 mg, and anhydrous magnesium sulfate of 150 mg, and 39 organophosphorus pesticides in the purified solution were determined by online gel permeation chromatography-gas chromatography tandem mass spectrometry (Online GPC-GC-MS/MS). As shown by the results, linear relationships of 39 organophosphorus pesticides were found in definite ranges, with detection limits (3S/N) in the range of 0.5-4.3 μg·kg-1. Test for recovery was made by standard addition method, giving results in the range of 83.1%-105%, with RSDs (n=6) all less than 9.0%.
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