A Rapid Screening Method for the Determination of Seventy Pesticide Residues in Soil Using Microwave-Assisted Extraction Coupled to Gas Chromatography and Mass Spectrometry

A rapid screening method using microwave-assisted extraction (MAE) in combination with gas chromatography and mass spectrometry for the determination of 70 pesticide residues in soil was established. The pesticides included 27 organophosphorus pesticides (OPPs), 29 organochlorine pesticides (OCPs), nine pyrethroids, and five carbamates. Parameters that could affect the efficiency of extraction, such as temperature, time, and solvent, were investigated. The condition of the extraction, under which recoveries of all 70 pesticides ranged from 70% to 120%, was optimized with a 1:1 (V/V) mixture of acetone and hexane, a temperature of 100°C, and an extraction time of 10 min. All compounds studied could be recovered in good yields and with relative standard deviations (RSDs) lower than 20%. The linearity of the method for all the pesticides was greater than 0.99 over a concentration range of 0.1–5 μg/g. The detection limits varied from 0.5 to 211.25 ng/g. Interday and intraday precision analyses yielded RSDs of 1.2%–11.7% and 3.6%–15.1%, respectively. This method, which was as effective as Soxhlet extraction and accelerated solvent extraction (ASE), proved to be accurate and precise. When the proposed method was used to examine environmental samples, the obtained results were in good agreement with those obtained using Soxhlet extraction.