Study On Stereoselection Adsorption And Degradation Behaviors Of Flumequine In Water And Sediment

Antibiotics pollution in the aquatic environment is one of research topic currently.Quinolones is widely applied in aquaculture industry and broadly remain in water body for its easy to deposit in sediment.Recent research is limit to detect the concentration of the residue in water environment instead of doing depth and systematic study on migration and transformation behaviors.Besides,that the chiral characteristics of Quinolones and their metabolites as well as the different toxicity of enantiomers are neglected is the reason that we cannot accurately evaluate the dietary and environment risks.This project selects quinolones antibiotic flumequine and its metabolite 7-hydroxyflumequine as the research objects and will develop chiral analytical methods of these drugs and their metabolites enantiomers in water and sediment.On the basis,the affecting factors of stereoselective adsorption and transformation rules of the enantiomers of flumequine in sediment will be investigated.Simultaneously,the enantioselective behaviors of adsorption and degradation rules of parent compounds and its chiral metabolites in the water and sediment will be investigated through the laboratory culture and pond trials studies.This study will provide important theoretical significance and actual value for the chiral quinolones research on environmental ecology risk assessment and thus provide test basis for the scientific use of this drugs.In this study,flumequine enantiomers and metabolites enantiomers were separated by chiral stationary phase and high performance liquid chromatography.The chromatographic conditions such as chiral stationary phase and mobile phase ratio were investigated.The solid phase extraction conditions and extractant were optimized.Finally,we established the detection methods of flumequine enantiomers and its metabolites enantiomers in water and sediment.Results showed that flumequine enantiomers reached baseline separation,when using 0.2% acetic acid water and acetonitrile as mobile phase,and the retention time of S-(-)-Flumequine and R-(+)-Flumequine was 12.5 min and 14.8 min,respectively.The four enantiomers of 7-hydroxyflumequine were well separated.The recoveries of flumequine enantiomers and 7-hydroxyflumequine were high than 70%,and showed a good linear between 1.0 ~ 200.0?g/L.The rapid,accurate and reliable methods established in this paper were available for quantitative analysis of quinolones antibiotic in water and sediment.The results of adsorption test showed stereoselective differences of flumequine in 1# and 3# sediment samples and the adsorbing capacity of S-(-)-Flumequine and R-(+)-Flumequine are higher than the racemate.Adsorption selectivity is related to sediment properties,the stereoselective differences of flumequine occurred in alkaline sediment samples,the pH values of the sediment were also determinate the adsorption capacity of the flumequine enantiomers.Degradation kinetics and selective degradation of flumequine enantiomers in sediments showed that the process of the degradation of flumequine enantiomers followed pseudo-first-order kinetic.Under natural conditions,the degradation of flumequine was shown to be enantioselective,and the R-(+)-Flumequine was preferentially degraded.Moreover,the degradation rate constant and degradation half-life of and flumequine enantiomers under sterile condition was smaller than that under natural condition.However,under sterilization conditions,the results revealed that the degradation of flumequine in the three sediments is not enantioselective.It can be concluded that the microorganism is the main reason for the stereoselective degradation of flumequine enantiomers in sediments,that is,the microorganisms play an extremely important role in the degradation process of flumequine.The degradation behavior of the flumequine enantiomers in sediments does not exist the mutual transformation between enantiomers.Meanwhile,the physical and chemical properties of sediments,such as pH value and organic matter content,can affect the degradation rate of flumequine.