title: Solid-phase extraction based on magnetic core-shell silica nanoparticles coupled with gas chromatography-mass spectrometry for the determination of low concentration pesticides in aqueous samples.
abstract: A simple and effective preconcentration method based on magnetic core-shell silica nanoparticles with C(18)-modified surface was developed for the analysis of pesticide residues in environmental water samples by gas chromatography-mass spectrometry. Several kinds of organophosphorous and pyrethroid pesticides including methamidophos, dichlorvos, orthene, phorate, dimethoate, carbofuran, bifenthrin, fenpropathrin, cypermethrin, fenvalerate, and deltamethrin were used as model compounds to systematically evaluate the method. Various parameters, including the amounts of magnetic nanoparticles absorbents, extraction time, eluting solvent, eluting volume, and sample pH values were optimized. The optimized method affords low detection limits (signal-to-noise ratio = 3) from 0.001 to 0.008 μg/L, and shows good linearity with correlation coefficients over 0.9990 in the concentration range of 0.025-0.5 μg/L. Average recoveries at three spiked levels were in the range of 70.2-110.2% with relative standard deviations below 9.6%. A maximum enrichment factor of 1015 times was achieved. Analysis results of poisoned pond water indicate that this method is fast, convenient, and efficient for the detections of low-concentration pesticides in aqueous samples.
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry, East China University of Science and Technology, Shanghai, PR China.
authors.forename: Zhichao
authors.initials: Z
authors.lastname: Xiong
authors.forename: Lingyi
authors.initials: L
authors.lastname: Zhang
authors.forename: Runsheng
authors.initials: R
authors.lastname: Zhang
authors.forename: Yurong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jianhu
authors.initials: J
authors.lastname: Chen
authors.forename: Weibing
authors.initials: W
authors.lastname: Zhang
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D009943:Organophosphorus Compounds / Q000032:analysis; D010575:Pesticides / Q000032:analysis*; D011722:Pyrethrins / Q000032:analysis; D012822:Silicon Dioxide / Q000737:chemistry*; D052616:Solid Phase Extraction; D013499:Surface Properties; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D058185:Magnetite Nanoparticles; D009943:Organophosphorus Compounds; D010575:Pesticides; D011722:Pyrethrins; D014874:Water Pollutants, Chemical; D012822:Silicon Dioxide