Determination of Nitrogen-containing Heterocyclic Pesticide Residues in Vegetables by Solid-phaseExtraction Coupling of Gas Chromatography-Mass Spectrometry

A solid-phase extraction (SPE) combined with gas chromatography-mass spectrometry (GC-MS) for the determination of four nitrogen-containing heterocyclic pesticides (anilazine, fipronil, buprofezin, thiabendazole) in vegetables has been developed. The sample was extracted with acetonitrile, purified on a homemade Florisil-SPE column and determined with GC-MS. The analytes were quantitated by monitoring ions and confirmed with the SCAN mode. The method showed good linearity (R≥ 0. 9953) and repeatability (RSD≤ 9.1% for the peak area). The limits of detection for the four pesticides were between 3.6~1.8×10^-4 μg/mL (S/N=3). Recoveries of the four pesticides ranged from 76.1% to 116.4% with RSDs ≤ 9.8%. The method was applied to the determination of trace pesticide residues in flowering Chinese cabbage samples from the local market with satisfactory results. The method is simple, accurate and suitable to the analysis of nitrogen-containing heterocyclic pesticides in vegetables.