GC Determination of Organophosphorus Pesticides in Water with Solid Phase Micro-extraction

GC with sample pretreatment by solid phase micro-extraction (SPME) was applied to the determination of residual amounts of 6 organphosphorus pesticides in water. To attain a higher efficiency for SPME, the 65 μm PDMS/DVB micro-extractor was selected, and the extraction was carried out at 80 ℃for 20 min, with addition of 1.5 g NaCl to 10 mL of sample solution as salting out agent. The analyte were separated on HP-5 capillary column and detected by ECD. Linear relationships between values of peak area and mass concentration of the 6 organphosphorus pesticides were kept in the same range of 1.0-50.0 μg·L-1, with detection limit (3S/N) in the range of 0.026-0.064 μg·L-1. The proposed method was applied to the analysis of water samples, giving values of recovery found by standard addition method in the range of 86.2%-115.7% with RSD′s (n=6) in the range of 3.0%-5.6%.