Studies On Analysis And Selective Environmental Behaviors Of Chiral Fungicide Penflufen Enantiomers

Enantiomers of chiral pesticides always exhibit significant stereoselective degradation,bioactivity and ecotoxicity in the chiral environment.Using traditional risk assessment method to evaluate the chiral compounds can hardly provide accurate and scietific guidence for the corresponding risk assessment which could result a series of potential safety hazard for human being and environment.So,it has becoming a imperative problem to investigating the enantioselective behavior of chiral compounds in organisms and environment.This article started from the enantioselective seperation and absolute configuration confirm of penflufen by liquid chromatography-tandem mass spectrometry(LC-MS/MS).And then the simultaneous determination method for the enantiomers of penflufen in four matrices were established.On the basis of the determination method,the stereoselective behavior of penflufen in wheat and soil were investigated for the first time.The results and conclusions were shown below:1.A method for separating penflufen was established by LC-MS/MS with reverse phase chiral stationary phase.The conditions of separating and mass spectrometry were optimized and the optimized detection conditions was selected with Lux 5u Cellulose-2 chiral column,0.1%formic acid buffer and acetonitrile as the mobile phase,the flow rate of 0.4 mL/min and gradient elution,the column temperature was kept at 35?.MS detection was performed by positive modes with ESI+and the parameters obtained by the pattern of MRM.After optimization,the quantitative ion m/z of penflufen was 329.05>31 7.30,the qualitative ions m/z were 329.05>314.00 and 329.05>306.002.The absolute configuration of penflufen enantiomers was confirmed by comparing the experimental and predicted ECD spectra.3.A simple and reliable method for the simultaneous determination of penflufen enantiomers in wheat plants and soil were established by LC-MS/MS and all samples were purified by the QuEchERS method.Acetonitrile and water were used as the extraction solvent,PSA as the adsorbent matrix dispersed solid phase for purification.penflufen put up excellent precision and accuracy in all matrices.The mean recoveries ranged from 79.3%?100.3%,with 0.4%?8.1%intra-day RSD.The LODs and LOQs for this method in eight matrices were calculated at 6.0 ?g kg-1 and 20 ?g kg-1.This study provided a method for simultaneous determination of penflufen enantiomers in agricultural products and soil.4.The stereoselective environmental behavior of penflufen was investigated in plant,vegetable and three kinds of soils under aerobic condition,respectively.The results showed that the concentration of penflufen enantiomers decreased with time;The penflufen enantiomer were degraded fast in plants and soils.The degradation rate in plant was faster than soil.There was no remarkably enantioselective degradation was observed with EF value from 0.5 to 0.55 for penflufen enantiomers in wheat plant cabbage and soil.Whereas remarkable enantioselective degradation was observed for penflufen enantiomers.The order was as follows:spinach(EF=0.65)>black soil(EF=0.61).The R-(+)-penflufen was preferentially degraded and the S-(-)-penflufen was accumulated.Enantioselective degradation was observed for penflufen in soils under indoor aerobic conditions and under indoor anaerobic conditions.The order of enantioselectivity for penflufen was isologous.But the R-(+)-penflufen and were preferentially degraded,and the S-(-)-penflufen was accumulated in the black soil under indoor aerobic conditions.