A new design of equilibrium hollow fibre liquid phase microextraction (HF-LPME) was developed for the determination of three freely dissolved organophosphorus pesticides (OPPs), i.e. diazinon (O,O-diethyl-O-2-isopropyl-4-methyl-6-pyrimidyl thiophosphate), chlorpyrifos (O,O-diethyl-O-[3,5,6-trichloro-2-pyridyl] phosphorothioate), and fenthion (O,O-dimethyl-O-4-methylthio-m-tolyl phosphorothioate) as model compounds. In this new design a 1.2-1.4 cm length of a hollow fibre (HF), inserted to the end of 20 cm copper wire and impregnated with organic solvent, was used to extract the freely dissolved concentration of OPPs in various water samples. The limits of detection (LOD) in reagent water using gas chromatography-mass spectrometry in the selected ion monitoring (SIM) mode was in the range of 15-80 ng L-1. The relative standard deviations of the analysis (inter- and intra-day) were 8.7-30%. The method was applied to the extraction of spiked lake and ground water samples. The ground water sample was spiked at 0.1 and 0.2 µg L-1 concentrations of the analytes under study and the average extraction efficiency at the two concentrations was below 1% showing the non-depletive nature of the extraction, meaning that the freely dissolved concentrations are measured as opposed to total concentrations. Good linearity was obtained for all of the analytes in both reagent water and lake water samples with correlation coefficients, R2, ranging from 0.991 to 0.996, in the concentration ranges of 25-400 ng L-1. The method was found to be very simple and inexpensive, with the possibility of running hundreds of samples in parallel with very minimal expenses for the determination of freely dissolved OPPs.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
freely dissolved concentration;
hollow fibre liquid phase microextraction;
Document Type: Research Article
Department of Chemistry, Addis Ababa University, Addis Ababa, Ethiopia,Department of Analytical Chemistry, Lund University, Lund, Sweden
Department of Chemistry, Addis Ababa University, Addis Ababa, Ethiopia
Department of Analytical Chemistry, Lund University, Lund, Sweden
November 1, 2008
More about this publication?