The widespread use of organophosphorus pesticides(OPs) poses a great threat to human health and has made the detection of OP residues in food an important task,especially in view of the fact that easy and rapid detect...The widespread use of organophosphorus pesticides(OPs) poses a great threat to human health and has made the detection of OP residues in food an important task,especially in view of the fact that easy and rapid detection methods are needed.Because OPs have inhibitory effects on the activity of α-naphthyl acetate esterase(ANAE) in plants,in this work we evaluated the possibility of detecting OPs in vegetables with ANAE extracted from commercial flour.The limits of detection(LODs) obtained for methamidophos,dichlorvos,phoxim,dimethoate,and malathion in lettuce samples with crude ANAE were 0.17,0.11,0.11,0.96,and 1.70 mg/kg,respectively.Based on the maximum residue limits(MRLs) for OPs in food stipulated by Chinese laws which are 0.05,0.20,0.05,1.00,and 8.00 mg/kg for methamidophos,dichlorvos,phoxim,dimethoate,and malathion,respectively,the esterase inhibition method with crude ANAE had sufficient sensitivity to detect the residues of dichlorvos,dimethoate,and malathion in lettuce,but it could not be used to guarantee the safety of the same samples if methamidophos or phoxim residue was present.The sensitivity of the method was improved by the use of esterase purified by ammonium sulfate salting-out.The LODs obtained for methamidophos and phoxim with purified esterase were lower than the MRLs for these OPs in food.This is a very promising method for the detection of OP residues in vegetables using crude or purified esterase because of its cheapness,sensitivity,and convenience.展开更多
基金Project supported by the National Basic Research Program (973) of China (No.2009CB119000)the National Natural Science Foundation of China (Nos.20707022,41073090,and 30771255)the Zhejiang Provincial Natural Science Foundation of China (No.Y507220)
文摘The widespread use of organophosphorus pesticides(OPs) poses a great threat to human health and has made the detection of OP residues in food an important task,especially in view of the fact that easy and rapid detection methods are needed.Because OPs have inhibitory effects on the activity of α-naphthyl acetate esterase(ANAE) in plants,in this work we evaluated the possibility of detecting OPs in vegetables with ANAE extracted from commercial flour.The limits of detection(LODs) obtained for methamidophos,dichlorvos,phoxim,dimethoate,and malathion in lettuce samples with crude ANAE were 0.17,0.11,0.11,0.96,and 1.70 mg/kg,respectively.Based on the maximum residue limits(MRLs) for OPs in food stipulated by Chinese laws which are 0.05,0.20,0.05,1.00,and 8.00 mg/kg for methamidophos,dichlorvos,phoxim,dimethoate,and malathion,respectively,the esterase inhibition method with crude ANAE had sufficient sensitivity to detect the residues of dichlorvos,dimethoate,and malathion in lettuce,but it could not be used to guarantee the safety of the same samples if methamidophos or phoxim residue was present.The sensitivity of the method was improved by the use of esterase purified by ammonium sulfate salting-out.The LODs obtained for methamidophos and phoxim with purified esterase were lower than the MRLs for these OPs in food.This is a very promising method for the detection of OP residues in vegetables using crude or purified esterase because of its cheapness,sensitivity,and convenience.
