Determination of organophosphorous pesticides in wastewater samples using binary-solvent liquid-phase microextraction and solid-phase microextraction:A comparative study

摘要

A simple and efficient binary solvent-based two-phase hollow fiber membrane (HFM)-protected liquid-phase microextraction (BN-LPME) technique for moderately polar compounds was developed.Six organophosphorous pesticides (OPPs) (triethylphosphoroth-ioate,thionazin,sulfotep,phorate,disulfoton,methyl parathion and ethyl parathion) were used as model compounds and extracted from 10-mL wastewater with a binary-solvent (toluenerhexane,1:1) mixture.Some important extraction parameters,such as extraction time,effect of salt,sample pH and solvent ratio composition were optimized.BN-LPME combined with gas chromatography/mass spectrometric (GC/MS) analysis provided repeatability (R.S.D.s < 12%,n = 4),and linearity (r < 0.994) and solid-phase microextraction provides comparable of R.S.D.S < 13%,n = 4 and linearity (r = <0.966) for spiked water samples.The limits of detection (LODs) were in the range of 0.3-11.4 ng L~(-1) for BN-LPME and 3.1-120.5 ng L~(-1) for SPME at (S/N = 3) under GC/MS selective ion monitoring mode.In addition to high enrichment,BN-LPME also served as a sample cleanup procedure,with the HFM act as a filtering medium to prevent large particles and extraneous materials from being extracted.To investigate and compare their applicability,the BN-LPME and SPME procedures were applied to the detection of OPPs in domestic wastewater samples.