| High performance capillary electrophoresis has developed as one of the most popular analytical method during the past decades owing to its quick analysis speed,high separation effienicy,and low-sample emissions.All of the advantages of CE made that it was very suitable for the precious samples such as biological sample in vivo and chiral analytes.However,CE oftentimes suffers from the shortcoming of inadequate detection sensitivity due to the small sample load and the short analysis length.All these shortcomings directly lead to the lower sensitivity of concentration detection and it has limited the application of the detection of trace components in complex samples.Therefore,effectively enhance CE sensitivity to promote the development and the applications of CE is one of the most important problems to be solved.Considering that and based on the provirus studies,we herein proposed the following novelty studies:1.The effect of leading ion mobility on the analytes focusing efficiency during an isotachphoresis(ITP)was discussed by using computer simulation.This work has an important reference value for the selection of leading ion of an ITP.2.Based on the on-line concentration method of electrokinetic superchargeing(EKS),the contents of amines in C57BL/6 brain during ischemia/reperfusion were determined.This work possessed practical reference value in the study of brain stroke and its prognoses.3.A new interfacie-free pseudo two-dimensional heart-cutting CE method was developed for simultaneous preconcentration and separation of 3 cationic compounds and 3 anionic compounds in urine samples.4.An acid labile sweep reagent based field enhanced sample injection-sweeping on-line concentration method was developed.With the established method over 21000 folds enhancement for the detection of propranolol enantiomers was achieved.It significantly improved the detection sensitivity of propranolol enantiomers.Moreover,the mechanism of the on-line concentration method,the analytical performance of the present method,and its application in the analysis of biological samples were also investigated.This thesis is divided into six chapters:1.In chapter 1: We reviewed the application and development of on-line concentration CE technology and also introduced its technology research status and development trend in recent years.2.In chapter 2: The effect of leading electrolyte mobility on the stacking efficiency of an isotachophoresis(ITP)process was studied by computer simulation.In this chapter,the whole stacking process of ITP was simulated by using Simul 5.0.Upon the using of constant current mode,the effect of leading electrolyte mobility on the migration and stacking of analytes were discussed.The results indicated that the closer of leading electrolyte mobility and analytes mobility,the more efficiency of stacking.3.In chapter 3: In this study,the amines including dopamine(DA),epinephrine(E),noradrenaline(NE),and isoprenaline(i-E)in the C57BL/6 mice brain tissue during cerebral ischemia/reperfusion were detemined by electrokinetic supercharging(EKS).Under the optimized conditions,the four analytes were concentrated and detected in 10 min.The limits of detection(LOD)ranged from 0.66 to 0.85 ng/m L.With the proposed method,the analysis of neurochemical amines in C57BL/6 mice brain tissue had been achieved successfully.Furthermore,the EKS method and two-photon fluorescence imaging technique were employed to investigate a short time brain ischemia injury and renovation of neuron function following reperfusion.Considering the ischemia-induced changes apparent in both fluorescence imaging and EKS results together,we concluded that a short time brain ischemia might repair spontaneously with restoring the blood flow.4.In chapter 4: Combining of CZE and t ITP,a new interface-free pseudo 2D heart-cutting CE method within a single CE running process was developed.The method achieved the simultaneous focusing and separation of six analytes including three cationics and three anions with over 100-fold enrichment.Under the optimum conditions,the RSD value of migration time for all the six analytes was below 2.8% and the recoveries were 94.9~104%.5.In chapter 5: With the first using of an acid labile sweeping reagent,a facile and highly efficient FESI-sweeping was developed for the determination of trace enantiomers propranolol by NACE.The concentrated method was achived through a sweeping owing to the static interaction of acid-labile anionic selector and cationic analytes,and then the concentrated analytes were released and focused at the boundary of acid sample solution and separation buffer due to the decomposing of selector in the acid sample solution.The main affecting factors on the concentration efficiency were systemically investigated.Under the optimum conditions,21000-fold sensitivity enhancement was achieved for PL enantiomers.Eventually,the FESI-sweeping method was applied to detect PL enantiomers in plasma,saliva and urine.6.In chapter 6: Conclusion. |
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