Enrichment of Organophosphorus Pesticides with Multi-walled Carbon Nanotubes as Efficient Solid-phase Extraction Material from Water

Objective The enriching effect of 16 rganophosphorus pesticides with multi-walled carbon nanotubes as efficient solid-phase extraction adsorbent from water was studied.Methods The determination and quantitation of 16 organophosphorus pesticides in water sample were carried out by gas chromatography-flame photometric detector(GC/FPD).The GC/FPD method used two columns(HP-50 and HP-1) and two FPD detectors.Results The clean-up conditions were optimized.The pH of water sample was adjusted 5.0 with HAc-NaAc buffer solution.MWCNTs SPE cartridge was pre-washed with 5 mL methanol and 5 mL HAc-NaAc buffer solution(pH 5.0).The water sample was transferred to the SPE cartridge.The cartridge was dried for 10 min under vacuum.The rganophosphorus pesticides were eluted with 10 mL dichlormethane into a graduated 10 mL centrifuge tube with ground-glass stopper and stand for 10 min.The upper water layer was transferred and threw away.The organic layer was dried under nitrogen.The remainder was re-dissolved with 2 mL acetone and determined by GC/FPD.The experimental results showed the methamidaphos was broken through,the recoveries of 9 organophosphorus pesticides(including phorate,diazinon,monocrotophos,dimethoate,pirimiphos-methyl ester,isocarbophos,quintiofos,methidathion,phthalophos) in water sample were over 75% and RSD were under 9%,and the recoveries of 6 organophosphorus pesticides(including trichlorphon,chlorpyrifos-methyl,chlorpyrifos,fenthion,ethion,phosalone) were under 64%.Conclusion This study indicates the MWCNTs SPE cartridge was an efficient clean-up and enrichment method to water and it can remove the contamination of the rganophosphorus pesticides in water.