CLOUD POINT EXTRACTION COUPLED WITH N-HEXANE BACK-EXTRACTION FOR DETERMINATION OF 5 KINDS OF ORGANOPHOSPHORUS PESTICIDES IN CIDER BY GAS CHROMATOGRAPHY

A method was developed for the determination of organophosphorus pesticides(diazinon,pyrimithate,thiophos,isofenphos and triazophos) in cider using cloud point extraction(CPE) coupled with n-hexane back-extraction and gas chromatography.Pesticides were extracted with the non-ionic surfactant Polyethylene glycol 4000.The surfactant-rich phase was back extracted by n-hexane.The apparatus was gas chromatography with flame photometric detector(FPD).The pesticide residues were calculated by external standard method.Good linearrelation was obtained over the range of 0.9986% ~ 0.9996% for these five organophosphorus pesticides in 0.05 ~ 2.00 mg/L.The average recoveries of the five organophosphorus pesticides were 72.5% ~ 102.6% with corresponding RSD of 1.97% ~ 7.85% in the amounts 0.0015 ~ 0.0300 mg/L.The limits of detection(LOD) was 0.13 ~ 1.50 μg/kg in this method.The method was simple,reproducible and of high sensitivity.