Determination Of Antibiotics In Environmental Samples By Capillary Electrophoresis Coupled With Ionic Liquid-hollow Fiber Liquid Phase Microextraction

Sulfonamides are widely used in animal husbandry and aquaculturefor their ability to prevent and control the spread of diseases.However,sulfanilamides are difficult to be degraded and have long residue time.Eventually,they will enter and remain in the environmental waters in various ways,affecting the quality of the environment and eventually posing threat to human health.Therefore,it is very important to establish a method for the detection of sulfonamides in environmental waters.Liquid phase microextraction based on hollow fiber（HF-LPME）is a new pretreatment technique which is environment-friendly and sampling,extraction and concentration can be carried out simultaneously.Ionic liquids,as a new green solvent,have been used in combination with hollow fiber liquid phase microextraction（HF-LPME）.It overcomes the shortcomings of traditional extraction solvents（organic solvents）and makes advantage of its inherent advantages.Therefore,it has a wide application prospect in the analysis of trace and ultra trace organic pollutants.In this study,hollow fiber liquid phase microextraction combined with ionic liquids was used to study the pretreatment of sulfonamide antibiotics in the environment water samples.The contents of the target were determined by capillary electrophoresis.Moreover,the related analytical method was established and successfully applied to the determination of environmental water samples.Specific work was as follows:Chapter 1 Firstly,the basic structure,principle and characteristics of capillary electrophoresis（CE）were introduced.On the basis of systematic introduction to liquid phase microextraction,four modes of hollow fiber liquid phase microextraction were also classified in detail.The composition,species and basic properties of ionic liquids are briefly introduced.In addition,the sulfonamide antibiotics were mentioned,including their structure,their harm to the human body,source in the environment water and relevant analytical methods.Chapter 2 A method was developed for the determination of 4 kinds of sulfanilamides in environmental water samples by hollow fiber liquid phase micro-extraction（HF-LPME）coupled with CE.The factors which affect the extraction efficiencies were investigated and optimized,including types of hollow fiber and extraction liquid membrane,the pH values of the donor phase and the acceptor phase,the volume ratio of the donor phase and the acceptor phase,the stirring speed,the salt concentration and the extraction time.The optimal extraction conditions were as follows:Accurel Q 3/2 polypropylene hollow fiber membrane was selected,1-octanol was used as the extractant,150 mmol/L NaOH solutions was chosen as the acceptor phase and KH₂PO₄ solution（pH=4.5）was adopted as donor phase,the stirring rate was 300 r/min and the extraction time was 60 min.Under the optimal extraction conditions,the developed method provided a wide liner range from 5 to1000μg/L（r≥0.9997）and the corresponding enrichment factors were within 105-393.When real water samples were spiked with the sulfanilamides at the levels of 20,50 and100μg/L respectively,the average recoveries of 82.4-100.6%were achieved,and the relative standard deviations（RSDs）were in the range of 0.4-6.6%.Three kinds of sulfonamides were detected in the sewage and aquaculture area.The developed method was proved to be sensitive,simple and accurate,and suitable for determination of sulfanilamides in environmental water samples.Chapter 3 A method was developed for the determination of sulfonamides in aquaculture water,which was called ionic liquid-hollow fiber liquid phase micro-extraction（IL-HF-LPME）coupled with CE.The single factor experiment was carried out to obtain the optimal extraction conditions.The optimization factors including hollow fiber composition,type of extractant,auxiliary extractant content,pH values of donor phase phase,concentration of acceptor phase,volume ratio,stirring speed,extraction temperature,extraction time,salt concentration and so on.Under the optimum conditions,the corresponding enrichment factors were within 122-230.It provided a wide liner range from5 to 1000μg/L（r≥0.9997）and the limits of the detection ranged from 0.33 to 1.42μg/L for the 6 sulfanilamides（S/N=3）.Real water samples were spiked with the sulfanilamides at the concentration levels of 10,50 and 100μg/L.As a result,the average recovery ranged from 84.4 to 100.7%,and corresponding RSDs were in the range within 0.8-8.9%.In this method,ionic liquid was chosen as extractant.It had the characteristics of environment-friendly,easy operation and reliable analytical results.The developed method was proved to be suitable for the analysis of sulfonamides residues in aquaculture water samples.