Application of solid-phase microextraction for the determination of organophosphorous pesticides in aqueous samples by gas chromatography with flame photometric detector

A method based on solid-phase microextraction and gas chromatography flame photometric detector for the determination of organophosphorous pesticides (OPPs) in aqueous samples was described. Five kinds of commercially available fibers—7, 30 and 100 μm PDMS, 85 μm PA and 65 μm PDMS-DVB—were compared and 100 μm PDMS and 85 μm PA were the most sensitive fiber coatings for the analytes. The extraction time, extraction temperature, pH and content of NaCl were found to have significant influence on extraction efficiency. The optimized conditions were 100 μm PDMS fiber, 30 min extraction time at 40 °C, with 3% NaCl content and no pH adjustment. The linear range was 0.5–100 μg l−1 for most of the analytes. The limits of detection (LODs) ranged from 0.049 μg l−1 (for parathion) to 0.301 μg l−1 (for carbophenothion) and RSD% of repeatability at the 10 μg l−1 level were all below 8%. Environmental water samples were analyzed, but none of the analytes was detected. The recovery of spiked water samples was from 75.3 to 102.6%.