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71.
Joon Myong Song 《Analytica chimica acta》2003,487(1):75-82
In this work, a combination of complementary metal-oxide semiconductor (CMOS) microchip system with capillary array electrophoresis (CAE) is demonstrated as a system for optimizing conditions for enzymatic reaction. Dimethylacridinone (DDAO)-phosphate substrate and alkaline phosphatase conjugate were selected for the enzymatic reaction, which was applicable to the enzyme-linked immunosorbent assay (ELISA) technique. Laser-induced fluorometry with a miniature semiconductor laser was used to detect the enzymatic products. The speed of the enzymatic reaction between the DDAO-phosphate and the alkaline phosphatase conjugate was investigated as a function of reaction time. The microchip-CAE detection system could determine the pH condition and the concentration of enzyme that are suitable for rapid and low-cost analysis. This result shows the feasibility of using the microchip-CAE system for application to miniaturized screening systems. 相似文献
72.
任意多阶梯度场强毛细管凝胶电泳中谱带的迁移和展宽 总被引:2,自引:0,他引:2
在自行制备的毛细管凝胶电泳柱上,通过实验考察毛细管凝胶电泳(CGE)中场强(E)和组分迁移率(μ)的关系,发现在一般CGE使用的场强范围内,μ随E增大而成近似线性的增加。并讨论了产生这种现象的原因。以此为基础提供了任意多阶梯度场强毛细管凝胶电泳中组分的迁移时间和距离的计算公式,用于编制计算机程序。 相似文献
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The low vapor pressure and the versatility of the physico-chemical properties of ionic liquids make them really attractive as an alternative for conventional molecular solvents. The knowledge of their physico-chemical properties (viscosity, conductivity, miscibility with organic solvents and anion-cation interactions) has appeared mandatory for better targeting their applications, although it is generally still lacking or incomplete.This work promotes capillary electrophoresis instrumentation as an integrated apparatus for measurement of viscosity, conductivity and absorbance of pure ionic liquids and ionic liquid-molecular solvent mixtures. Compared to current conventional techniques, the assets of this instrumentation for this purpose are the combined availability of a pressure delivery system, power supply, diode array absorbance detector and thermoregulation device, allowing unattended, automatic and easy operation, involving minimum sample handling. Most importantly, the required sample volume can be reduced to about 50 μL, making this protocol very cost-effective. A protocol was optimized with respect to time, sample consumption and data reliability for the determination of these physico-chemical parameters. Ionic liquids selected for method development and validation differed in the nature of their cation (butyl- and ethyl-methylimidazolium) and anion (trifluoromethanesulfonate and bis(trifluoromethanesulfonyl)imide). Various molecular solvents were mixed with these ionic liquids (acetonitrile, methanol, dimethylformamide and trifluoroethanol) and the same physico-chemical properties were determined by optimized methods. The knowledge of these data should be of great support in various application areas, including the development of new separation media for capillary electrophoresis and chromatographic techniques. 相似文献
76.
As an extension of previous reports, the barium carbonate procedure has been optimized in detail for the preparation of apolar columns. The aim was to produce optimum overall column characteristics, and to maintain them unchanged under the prolonged influence of the highest possible temperature. The main parameters under optimization were glass variety, leaching of glass surface with aqueous HCl, and amount of barium carbonate deposited, while deactivation and coating were kept constant. The basic column characteristics were adsorption properties and thermostability of deactivation, acid/base behaviour and separation efficiency. They were determined by a new, quantitative testing procedure. Intense leaching was able to eliminate almost totally the differences between glass varieties and to create a well-defined glass surface. While untreated glass, leached glass, and barium carbonate treated glass showed specific weak points in the respective column quality, the combination of leaching and barium carbonate treatment yielded the highest and most stable quality. Some technical modifications of the preparation procedure are described, including deactivation in the gas phase, and use of pentane as a solvent for static coating. 相似文献
77.
3-Amino-1,2,4-triazole (amitrole) is a widely used pesticide, with many difficulties to be analyzed at the regulatory level in drinking water, because its high solubility in water. This paper describes a simple and fast method for the simultaneous determination of amitrole and atrazin-2-hydroxy, principal degradation product of s-triazines, by capillary zone electrophoresis. Separation and determination of these herbicides in water samples was performed in 0.02 mol l−1 phosphate buffer at pH 3.2. The method allows determination of the amitrole and atrazin-2-hydroxy in water samples in concentration lower than 100 μg l−1. The detection limits using a previous preconcentration step of amitrole in Alberche River (Comunidad Autónoma de Madrid, Spain) and drinking water spiked samples was of 4 μg l−1. 相似文献
78.
《Electroanalysis》2005,17(8):706-712
Capillary electrophoresis with amperometric detection was applied to determine some β2‐agonists, such as clenbuterol, cimaterol and salbutamol in this paper. The working electrode used was a 0.3 mm diameter carbon disk electrode. In this work, the pH 6.0–6.4 borax‐potassium dihydrogen phosphate was used as running buffer (150 mmol/L), 10 kV as the separation voltage and 1.05 V (vs. Ag/AgCl, 3 mol/L KCl) as the detection potential. Under the optimum conditions, the analytes were baseline separated within 16 min. Linear range for cimaterol, clenbuterol and salbutamol was 1.0–2000, 2.0–2000 and 1.0–2000 ng/mL, respectively. The detection limits (define as 3σ/k) were 0.5, 1.0 and 0.4 ng/mL for cimaterol, clenbuterol and salbutamol, respectively. The developed method has been applied to determine these three analytes in feed and urine by standard addition. The mean recoveries for these three analytes ranged from 89.0% to 102.0%. 相似文献
79.
Ursula Ehrmann Lante Carbognani Claudio Ceccarelli 《Journal of separation science》1992,15(7):467-471
Two methods have been developed for the determination of trace levels of acetonitrile and propionitrile in light naphthas. One involves clean-up and preconcentration by medium pressure liquid chromatography (MPLC) in which nitriles are concentrated ten-fold while the complex hydrocarbon matris is removed. The concentrated solution is then analyzed by high resolution GC with flame ionization detection. The second method involves direct injection of samples into a capillary GC equipped with chemiluminescence nitrogen detection. The results and repeatability obtained from both methods are comparable. Preconcentration enables identification by GC-MS and simultaneous analysis of other polar species, with no need for selective detectors. Direct analysis is, on the other hand, much less time-consuming and requires less sample. 相似文献
80.
Eckhard Spohr Andrij Trokhymchuk Douglas Henderson 《Journal of Electroanalytical Chemistry》1998,450(2):211
We report molecular dynamics (MD) simulations on the adsorption of water in attractive and repulsive slit pores, where the slit and a bulk region are in contact with each other. Water structure, surface force and adsorption behavior are investigated as a function of the overall density in the bulk region. The gas–liquid transition in both types of pores occurs at similar densities of the bulk region. 相似文献