Study On Enantioselective Behavior Of Chiral Ethiprole In Grape、Eggplant、Pepper And Earthworm

In recent years,pesticides have been developing towards environmentally friendly,low toxicity and high efficiency in response to the national double reduction policy.The development and utilization of Chiral pesticide optical isomers are promoted greatly.Currently,most chiral pesticides are still sold in the form of racemates.Enantiomers of a chiral chemical have the same physicochemical properties,when they exposed to environment systems,Enantiomer show different selectivity in metabolism,bioaccumulation,excretion,absorption and other environmental behavior.Traditional evaluation methods of chiral pesticides are only developed from the perspective of racemate,which results in unreliable results of environmental risk assessment of chiral pesticides and brings potential risks to human health and environmental safety.This paper study on enantioselective environmental behavior of the chiral pesticide ethiproleand provides a theoretical basis for the environmental risk assessment of the chiral pesticide ethiprole.The main research contents are as follows:（1）In this experiment,the separation of enantiomers of ethiprole was completed by means of supercritical fluid tandem mass spectrometry,the optimal chiral column od-3 was screenedand the conditions of supercritical fluid such as organic modifier type,Proportion of the organic modifier,flow rate,ABPR pressure,column temperature and,compensating pump flow rate were optimized to realize the base line separation of ethiprole enantiomers.Optimal separation condition was achieved with IA column using CO₂/isopropanol（90:10）as mobile phaseat 1.8m L/min in 4 min,30℃and 2000 psi,and compensation pump flow rate of 1.0ml/min.The elution order of ethiprole enantiomers were determined.（2）The residue analysis method of Ethiprole enantiomers in grape,eggplant and pepper was established for the first time.The precision and accuracy of this method are evaluated in this experiment.The average recovery of Ethiprole enantiomers in grape,eggplant,pepper was 91.2%-111.9%,94.2%to 111.9%and 85.4%-106.1%,RSDs of inter-day is 1.7%-6.5%,1.0%to 6.7%and 1.0%-8.8%,RSDs of intra-day is 3.9%to 7.6%,2.4%to 6.2%,2.7%to 7.8%.LOQ of the method in grape,eggplant and pepper is 0.01mg/kg,which meets the detection requirements of pesticide residues in environmental samples.Experimental results show that（+）-ethiprole was preferentially degraded in grape,and（-）-ethiprole preferentially degraded in eggplant.EF of ethiprole enantiomers in pepper fluctuate at 0.5which indicated that no significant enantioselectivity.In this study,the functional enzymes may bedifferent in different plants（grape、eggplantand pepper）and the different functional enzymesmay result in differences in enantioselective dissipations.（3）There is an analytical method for the enantiomer of ethiprole in earthworms was established by SFC-MS/MS for the first time in this experiment.The method of combining Qu ECh ERS method with PC/PSA solid phase extraction column as the pretreatment method of earthworms and the precision and accuracy of the method have been validated.The purification result is effective,and the recovery rate is between 80%and 120%.（-）-ethiprole is more likely to accumulate in the earthworm Among the three concentration.The concentration of earthworms is related to the concentration of pollutants in the soil.As the exposure concentration increases,the BSAF value becomes smaller.