Determination of ethoprop, diazinon, disulfoton and fenthion using dynamic hollow fiber-protected liquid-phase microextraction coupled with gas chromatography-mass spectrometry.

A technique for the analysis of organophosphorus pesticides (ethoprop, diazinon, disulfoton, fenthion) in aqueous sample using liquid-phase microextraction (LPME), coupled with gas chromatography-mass spectrometry (GC-MS) was developed. A small section of a hollow fiber inserted into the needle of GC syringe and filled with the 3.5mul of organic solvent was used to extract pesticides from a 20ml aqueous sample. The limits of detection (LOD) with the selected ion monitoring (SIM) mode varied from 0.2 to 0.006mug/l. The calibration curves were linear over three orders of magnitude with R(2)>/=0.996. The relative standard deviations of the analysis (inter- and intra-day) were 5-8%, and the relative recoveries from the lake water sample were greater than 83%. The results were compared with results obtained using solid-phase microextraction (SPME/GC/MS).