| After recent years of development,capacitively coupled contactless conductivity detector have attracted more and more attention as a detection technology for capillary electrophoresis,especially in ion detection.Because of the response of common ultraviolet detection and fluorescence detection to ions is not ideal,and the capacitively coupled contactless conductivity detector can be used as a general-purpose detector to detect charged ions,such as inorganic ions,organic ions,and biochemical substances.In this work,we used capillary electrophoresis capacitively coupled contactless conductivity detector built in the laboratory to detect disease markers in blood samples,additives in drugs and food.This dissertation is mainly divided into the following four chapters:Chapter 1:We summarized the principles of capacitively coupled contactless conductivity detector(C~4D)and the progress of optimizing instrument briefly,and summarized its applications in detecting food,drug,and biological sample.Chapter 2:Potassium ion channel gene mutations are highly correlated with the incidence of many primary epilepsy that may affect the potassium level in blood,but complicated matrices of the blood sample may cause significant variation of migration times and peak shape.In this work,a procedure for rapid stabilization of the capillary inner surface through pre-flushing of a blood sample was employed.The process takes only 40 min for a capillary and then it can be used for more than 2 weeks.No pretreatment of the blood sample or other surface modification of the capillary is needed for the analysis.The relative standard deviations(RSDs)of the migration time and peak area were reduced to 1.5%and 5.1%from 12.6%and 14.5%.The proposed method has been successfully applied to the determination of the potassium contents in blood of patients with epilepsy at different stage.It’s a simple and easy detection method for the diagnosis and treatment of epilepsy.The recoveries of potassium ions in these blood samples are ranged from 86.5 to 104.5%,it has good practicality.Chapter 3:Fetal bovine serum was used to passivate the inner wall of the capillary,the CE-C~4D device built by the laboratory was used to detect Li~+in blood samples.The limit of detection was 1.50?mol/L and the limit of quantification was 5?mol/L.The RSD values of Li~+for migration time and peak area before and after the coating were changed from 16.8%and 23.2%to 1.6%and 5.3%,respectively,indicating that the method has good practicability.At the same time,the separation and detection of levodopa,dopamine,arginine and epinephrine were completed using the coated capillary.The RSD values of the migration time and peak area of the four neurotransmitters are between 0.33%-0.76%and 3.98%-6.15%,respectively,with good reproducibility.It provides a practical way for the detection and judgment of various diseases.Chapter 4:A method based on capillary electrophoresis capacitively coupled contactless conductivity detector was established for the separation and detection of six artificial sweeteners in drugs and beverages.The results show that under the optimal conditions(separation voltage 18 kV,BGE is 10 mmol/L triethylamine,pH 11.2),aspartame,cyclamate,acesulfame,saccharin,saccharin sodium and neotame and can achieved baseline separation within 3 minutes,linear relationship is good,correlation coefficient(R~2)is greater than 0.99,limit of detection(S/N=3)is 0.002-0.034 g/mL,limit of quantification(S/N=10)is 0.01-0.11 g/mL,the relative standard deviation(n=6)is 5.2%-6.7%.The method has good stability and accuracy for the detection of sweeteners in drugs and beverages,and provides a portable method for the detection of flavoring agents in drugs and beverages. |
