Microextraction in packed sorbent for the determination of pesticides in honey samples by gas chromatography coupled to mass spectrometry.

The present work describes the development and analytical validation of a method involving microextraction packed sorbent and gas chromatography coupled to mass spectrometry (MEPS-GC-MS) for the multi-residue analysis of 22 pesticides (permethrin, fenpropathrin, aldrin, α-hexachlorocyclohexane, β-hexachlorocyclohexane, lindane, vinclozolin, endosulfan, heptaclor, dodecaclor, tetradifon, 1,1-dichloro-2,2-bis (p-chlorophenyl)ethane, 1,1-bis(p-chlorophenyl)-2,2-dichloroethylen, carbofuran, carbaryl, pirimiphos methyl, chlorpyriphos, dimethoate, disulfoton, fenamiphos, terbufos and profenofos) in honey samples. The MEPS variables of sample pH, draw-eject cycles, ionic strength and desorption procedure were optimized to improve the sensitivity of the proposed method. The method was shown to be linear at concentrations ranging from 2, 5 and 10 ng/g (limit of quantification) to 75-100 ng/g. These values are lower than those established as the maximum residue limits for honey samples. The accuracy values (82-114%) were adequate for all the analytes, as were the inter-day precision data, with coefficient of variation lower than 14%. On the basis of analytical validation, the MEPS-GC methodology has been shown to be a promising alternative for the analysis of pesticides in honey samples. The MEPS packed syringe can be reused 40 times for honey samples, whereas the conventional solid-phase extraction (SPE) column can only be used once. Compared with liquid-liquid extraction and SPE, MEPS is able to reduce sample preparation time and organic solvent consumption.