ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Residue analysis of fosthiazate in cucumber and soil by QuEChERS and GC-MS
Min Wu and Jiye Hu
School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
Abstract: A convenient method was developed for the determination and validation of fosthiazate in cucumber and soil. The procedure is based on liquid partitioning with acetonitrile followed by dispersive solid phase extraction as the clean-up step, after which samples were analysed by gas chromatography-mass spectrometry (GC-MS). The average recoveries ranged from 91.2 % to 99.0 % with relative standard deviations (RSDs) of less than 6.05 %, at three fortification levels (0.02 mg kg−1, 0.1 mg kg−1, 0.5 mg kg−1) in cucumber and soil, and the limits of quantification (LOQs) for fosthiazate were all established at 0.02 mg kg−1. The proposed method was applied successfully to analyses of the dissipation and residue of fosthiazate in field trials. The dissipation rate of fosthiazate was described using pseudo-first-order kinetics with a half-life of 4.33 days and 4.08 days in soil in Beijing and Shandong, respectively. In the terminal residue experiment, fosthiazate residues in cucumber and soil were clearly below the maximum residue level (MRL, 0.2 mg kg−1) set in China.
Keywords: fosthiazate – cucumber – soil – GC-MS – QuEChERS – dissipation and residue
Full paper is available at www.springerlink.com.
Chemical Papers 68 (10) 1368–1374 (2014)