Research And Application Of On-line Coupling Method Of Headspace In-tube Micro-extraction And Capillary Electrophoresis

Capillary electrophoresis(CE)is an established microseparation technique.Chemiluminescence(CL)detection is known as an attractive detection scheme in CE due to its low background nature,high sensitivity,a wide linearity range,and simple instrument requirements.Focusing on separation techniques,capillary electrophoresis(CE)is attractive for the analysis of questioned documents: it possesses high versatility,is less expensive than other separation techniques,needs minimal amount of sample,almost no environmental pollution and also provides higher sensitivity than other techniques like vibrational spectroscopy,which can be of interest for differentiation processes.Thus,the CE-CLanalytical technique has been deployed to determine various types of biomedical molecules in complex samples such as serum and other physiological fluids.Unfortunately,CE-CL assay lacks high sensitivity compared with conventional CL assay techniques because only a very small amount of sample was introduced into the system for analysis.This technique was difficult for the detection of trace substance in biological samples.Therefore,the development of highly sensitive detection schemes for CE-CL assay has became an important issue.In view of this,the following major research and innovative work was performed in this dissertation.1.We designed and produced headspace in-tube mico-extraction(HS-ITME)units and described the method,characteristics and influencing factors.The units can be carried out coupling on-line with CE,which can effectively improve the concentration sensitivity of CE and simplify operation procedure of sample preparation.2.We utilized the on-line combination of HS-ITME and CE to determine phenolic compounds in varied nature water.The extraction conditions(extraction temperature,extraction time,salinity and sample volume)and separation conditions were investigated and optimized.Finally,the proposed method was proved to improve the detection sensitivity of CE effectively.3.Based on the separation mechanism of MEKC,we utilized the on-line combination of HS-ITME and RE-MEKC to determine PAEs in varied nature water and commercial beverages.The extraction conditions and separation conditions were investigated and optimized.Finally,the proposed method was proved to improve the detection sensitivity of CE effectively.4.Based on the experimental principle and results of 3,we continue to utilize the on-line combination of HS-ITME and CE to detect residual pesticide residues in fruits.The extraction conditions and separation conditions were investigated and optimized.Finally,the proposed method was proved to improve the detection sensitivity of CE effectively.5.Based on the experimental principle and results of 1,we utilized the on-line combination of HS-ITME and CE,which was added with ionic liquid into the buffer solution.The extraction conditions(species and concentration of ionic liquids was added based on 1)and separation conditions were investigated and optimized.Finally,the proposed method was proved to improve the detection sensitivity of CE effectively.