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Capillary electrophoresis (Capillary Electrophoresis, CE) is ions and charged particles to high voltage electric field as the driving force for the separation by capillary channel, according to the sample mobility between the components and / or distribution coefficient differences to achieve efficient and rapid separation A new type of liquid separation technology. Capillary electrophoresis is an efficient, fast, economical, environmental protection, etc., which are widely involved in the research and application of food hygiene, drug separation, environmental analysis, biochemical analysis, almost all areas of analysis. Capillary electrophoresis coupled with a variety of detection technologies, such as UV detection, fluorescence detection, electrochemical detection and mass spectrometry. Among them, the electrochemical detection of amperometric detection technology, relatively high sensitivity and wide linear range, the instrument is simple, low cost, easy to operate, and thus capillary electrophoresis - amperometric detection in analytical chemistry fields have been increasingly extensive research, application and development. This thesis is based on capillary electrophoresis - amperometric detection technology combined with efficient, rapid, sensitive and convenient advantages, the development of chemically modified electrodes from the start, for beverages, amino acids, chrysanthemum, hair dyes and other food and daily necessities in the active or toxic constituents separation and detection. Only extends the capillary electrophoresis - amperometric detection combined with the application of techniques to improve the detection sensitivity, improved separation efficiency, and further to create a new method for simultaneous determination of experimental phenylenediamines and dihydroxybenzene isomers other similar a complex system, to obtain a good result. Thesis is divided into the following seven sections: The first chapter briefly reviews the history of development of capillary electrophoresis, the basic principle of separation mode, combined with detection technology, research and application areas of this thesis the purpose and significance. The second chapter studies the simultaneous production of cuprous oxide with polyethylene glycol and a new pair of modifier modifier carbon paste electrode (PEG-Cu 2 O CPME), and the first will be applied to sugar substances and ascorbic acid by capillary zone electrophoresis - amperometric detection. In the study, the experiment investigated various experimental parameters affecting the separation and detection, the ultimate success of the realization of glucose, sucrose, fructose and ascorbic acid at the same separation and detection. With unmodified pure carbon paste electrode or contain only one carbon paste electrode modifiers compared, PEG-Cu 2 O modified carbon paste electrode at a relatively lower detection potentials (0. 30 V vs.SCE) has good catalytic oxidation characteristics, sensitivity, improved significantly. Under optimal experimental conditions, this new modified carbon paste electrode as working electrode, the four components can be obtained within 22 min a complete separation and detection. Glucose, sucrose, fructose, ascorbic acid and the linear range is 1.0 × 10 -6 ~ 5.0 × 10 -5 mol L -1 , the lowest detection limit reached 1.0 × 10 -7 mol L -1 of magnitude (N = 3). Experimental results show that this law has a high separation efficiency, analysis of simple operation, high sensitivity, good reproducibility, etc., on the real samples obtained satisfactory results. Chapter III for the first time the use of multi-walled carbon nanotubes and cuprous oxide while doing a carbon paste electrode modifier determined 19 kinds of essential amino acid. Due to the lack of amino acids for the detection of the optical properties such as light absorption, light emission and electrochemical activity, it is often necessary to have a variety of techniques derived from optically active or electrochemical activity. This derivative abandon the traditional method, the application of multi-walled carbon nanotubes and cuprous oxide modifier of carbon paste electrode pairs were determined 19 kinds of essential amino acid. Study found that this modified electrode, 19 amino acids of the electrochemical response of the pH of the buffer solution has a close relationship and to further explore the reaction mechanism. The application of the modified carbon paste electrode successfully electrochemical response among six kinds of high amino acids (arginine, tryptophan, histidine, threonine, serine, tyrosine) conducted a capillary zone electrophoresis - Amp testing. Under optimum conditions, the six kinds of analytes can be baseline separated within 20 min, the detection limit of 10 -7 ~ 10 -8 mol L -1 of magnitude (N = 3), the method is simple, high sensitivity, the test results are satisfactory. Chapter A novel poly VB 12 modified electrode and applied capillary electrophoresis - simultaneous separation and detection of amperometric detection fruits and vegetables antioxidants. Compared with ordinary carbon electrodes, this modified electrode glutathione, ascorbic acid, vanillic acid, chlorogenic acid, salicylic acid and caffeic acid nature of the electrochemical oxidation was significantly improved. The modified electrode for capillary electrophoresis - amperometric detection, capillary electrophoresis investigated influence of various factors: the pH buffer system and solution concentration, separation voltage, detection potential, the injection time. Under optimal experimental conditions, these six antioxidants in pH 8.4 borax - phosphate buffer completely separated within 15 min. And wide linear range 2.5 × 10 -7 ~ 1.0 × 10 -4 mol L -1 , the detection limit of 10 -7 ~ 10 -8 mol L -1 of magnitude (N = 3). The results showed that: this method is simple, sensitive, reproducible and good benefits, can be used in real samples. Chapter by capillary zone electrophoresis - amperometric detection technology to achieve the hair dye o, m, p-phenylenediamine and neighbors, resorcinol isomers of separation and detection. The effects of pH and concentration of buffer solution, separation voltage, detection potential, injection time and other experimental parameters on the impact of separation and detection. Under the optimal experimental conditions, with a Pt electrode as the working electrode, the potential of 0.85 V under test, the five analytes baseline separation within 15min, the linear range of 1.0 × 10 (-6) ~ 1.0 × 10 (-4) mol L -1 , the lowest detection limit of up to 10 -7 mol L -1 of magnitude ( N = 3). Experiment is successful separation and detection of eight kinds of hair dye samples of the five isomers, recoveries were 91.0 ~ 108.0%, the relative standard deviation is less than 5.0%. The results show that using a platinum electrode as the working electrode used in capillary zone electrophoresis - amperometric detection has simple operation, high sensitivity, low detection limit, good reproducibility, etc., can be used for the rapid detection of real samples. Chapter VI of this paper chrysanthemum flavonoids, through experiments tested a variety of buffer additives on capillary electrophoresis - amperometric detection results of the impact, and ultimately establish a suitable buffer additive and add location, the realization of flavonoids in chrysanthemum material separation and detection. And capillary electrophoresis experiments to optimize the parameters in the optimal experimental conditions, the carbon disk electrode as working electrode, six kinds of flavonoids in baseline separated within 20 min, the lowest detection limit reached 10 -8 < / sup> g mL -1 . Experimental results show that the use of the optimized capillary zone electrophoresis - amperometric detection, separation and detection with high sensitivity and good reproducibility for chrysanthemum real samples with satisfactory results. Chapter VII of the application run alternately two different pH value of buffer solution capillary electrophoresis - amperometric detection, can achieve a good separation of isomers detected and simple operation, high sensitivity, reproducibility, good for capillary electrophoresis methodology study provides a new direction. Since o-, m-, p-phenylenediamine pK a values ??were 4.52,5.64,6.04, and can therefore be separated acidic conditions to achieve good detection, and o-, , hydroquinone pK a values ??were 9.40,9.40 and 10.04, only in the alkaline buffer conditions to achieve good separation results. Therefore, the pH buffer with a fixed simultaneously isolated from all six isomers is very difficult (even in Chapter optimal conditions, it can only five of them to achieve the same separation and detection of isomers) . This paper designs and applications run alternately two different pH value of buffer solution capillary electrophoresis - amperometric detection simultaneous determination of these six isomers, the experimental results show that when a good control of two different pH buffer solution (pH respectively, 5.8 and 7.6) running time and order of these six analytes can be achieved within 20 min baseline separation, detection limit 10 -7 mol L -1 of magnitude (N = 3). To broaden the application of this method to study the feasibility of, we apply this method to other complex systems, found that different pH running buffer and the time to reach optimum operating sequence, it can successfully replace the buffer solution was added modifier separation and detection of chrysanthemum flavonoids (Chapter VI experimental) method saves time and effort, no organic solvent contamination.
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