Determination of 16 polycyclic aromatic hydrocarbon and 23 organochlorine residues in soil by accelerated solvent extraction and magnetic solid phase purification- gas chromatography-tandem mass spectrometry

Abstract

A method combining accelerated solvent extraction (ASE) with magnetic solid-phase extraction (MSPE) and gas chromatography-mass spectrometry (GC-MS) was developed for the simultaneous detection of polycyclic aromatic hydrocarbon (PAH) and organochlorinepesticide (OCP) residues in soil samples. The analytes in the soil samples were extracted using an acetone/n-hexane (1:1, v/v) mixture for 5 min at 100℃. Then, the extraction pool was heated for 5 min under an extractive pressure of 11.032 MPa for three cycles. The extraction pool was washed with an acetone/n-hexane (1:1, v/v) mixture accounting for 60% of the pool volume, followed by nitrogen purging for 100 s. The extract was purified by MSPE using self-made magnetic ZIF-8/nZVI materials at room temperature. The analytes were detected by GC-MS/MS. Under the optimized conditions, good linearities were obtained for the 16 PAHs and the 23 OCPs in the range of 5-200 μg/kg, with correlation coefficients (r2) above 0.99. The limits of detection (LODs) were 0.04-1.21 μg/kg. At three spiked levels in the soil samples, the recoveries of the 39 analytes were between 63.9% and 112.1%, with relative standard deviations (RSDs) between 0.4% and 26.2%. The method was demonstrated to be successful for the determination of 16 PAH and 23 OCP residues in soil samples, with good recoveries.