Multi-residue determination of pesticides in water using multi-walled carbon nanotubes solid-phase extraction and gas chromatography-mass spectrometry

A reliable multi-residue method which was based on solid-phase extraction (SPE) with multi-walled carbon nanotubes (MWCNTs) as adsorbent was developed for determination and quantitation of 12 pesticides (carbofuran, iprobenfos, parathion-methyl, prometryn, fenitrothion, parathionethyl, isocarbofos, phenthoate, methidathion, endrin, ethion, methoxychlor) in surface water by gas chromatography-mass spectrometry (GC-MS). Parameters that might influence the extraction efficiency such as the eluent volume, the sample flow rate and the sample loading volume were optimized. The experimental results showed the excellent linearity of 12 pesticides (R-2 > 0.99) over the range of 0.04-4 mu g L-1, and the precisions (RSD) were 3.1-15.1% under the optimal conditions. The detection limits of proposed method could reach 0.01-0.03 mu g L-1 based on the ratio of chromatographic signal to base line noise (S/N = 3). Good recoveries achieved with spiked water samples were in the range of 82.0-103.7%. The results indicated that MWCNTs have good adsorbability to the 12 pesticides tested in this study. With less cost, less analytical time and less solvent-consuming, the developed multi-residue method could be used to determine multi-class pesticides in water simultaneously. (c) 2007 Elsevier B.V. All rights reserved.