Quantitative measurement of collagen methylation by capillary electrophoresis

Collagen methylation has been exploited in various applications involving living cells. We have observed correlation between the collagen methylation with the rate of cell proliferation in three-dimensional (3-D) microenvironment. To quantify the degree of collagen methylation, we have developed a capillary zone electrophoresis method. Using a polyvinyl alcohol-coated fused-silica capillary and UV detection at 200 nm, we have optimized pH and separated the native collagen into three major bands in phosphate buffer (50 mM, pH 2.5) with 0.05% hydroxypropylmethylcellulose. Under these conditions, the methylated collagens were separated into four major bands, which changed with different methylation reaction conditions. We propose an index to quantify the degree of collagen methylation that also correlates with their effects on cell proliferation.     

Application of an integrated microchip system with capillary array electrophoresis to optimization of enzymatic reactions

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.     

使用二元环糊精体系毛细管电泳法分离手性药物

采用高效毛细管区带电泳法，分别以羟丙基-β-环糊精（HP-β-CD）和高磺化-β-环糊精（HS-β-CD）及二者混合物为手性选择剂，研究了5种药物的对映体分离，并取得很好的对映体分离结果。比较了HP-β-CD和HS-β-CD手性识别能力，分析了二元环糊精体系的“协同效应”。     

不依赖于统计模型的手性毛细管电泳分离多指标同时优化

考虑到手性毛细管电泳分离机理的复杂性，提出了不依赖于统计模型的二进制编码遗传算法多目标优化策略。根据实验参数的多少及其重要性，采用均匀设计安排完成初步实验。并用Derringer功效函数作为多指标同时优化的评价指标，以取得较高的分离度和较快分离速度；通过对实验参数给予编码，转化为二进制字符串，根据得到的总功效函数值大小进行遗传算法操作，产生新的一组实验条件。重复上述过程直到得到最佳分离条件为止。此方法成功地应用于华法令对映体的毛细管电泳分离条件优化。     

任意多阶梯度场强毛细管凝胶电泳中谱带的迁移和展宽

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。     

Poly(methacrylic acid-ethylene glycol dimethacrylate) monolith in-tube solid-phase microextraction applied to simultaneous analysis of some amphetamine derivatives in urine by capillary zone electrophoresis

A method based on in-tube solid-phase microextraction and capillary zone electrophoresis (CZE) was proposed for simultaneously determining four amphetamines (amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, and 3,4-methylenedioxymethamphetamine) in urine. A poly(methacrylic acid-ethylene glycol dimethacrylate) monolithic capillary column, which can provide sufficient extraction efficiency, was introduced for the extraction of amphetamines from urine samples. The hydrophobic main chains and acidic pendant groups of the monolithic column make it a superior material for extraction of basic analytes from aqueous matrix. After extraction, the samples were analyzed by CZE. The best separation was achieved using a buffer composed of 0.1 M disodium hydrogen phosphate (adjusted to pH 4.5 with 1 M hydrochloric acid) and 20% methanol v/v, with a temperature and voltage of 25 degrees C and 20 kV, respectively. By applying electrokinetic injection with field-amplified sample stacking, detection limits of 25-34 microg/L were achieved. Excellent method of reproducibility was found over a linear range of 0.1-5 mg/L. Determination of these analytes from abusers' urine sample was also demonstrated.     

Stochastic simulation of reactive separations in capillary electrophoresis

A stochastic (Monte Carlo) simulation is used to investigate thermodynamic and kinetic contributions from the reversible A <--> B reaction in capillary electrophoresis (CE). The effects of equilibrium constant, rate constant, and electrophoretic mobility on the molecular zone profiles and the corresponding statistical moments are evaluated. As the reaction approaches steady state, the velocity of the zone is governed by the equilibrium constant and the electrophoretic mobilities of the reacting molecules. When the equilibrium constant is less than unity, the mean zone velocity is more similar to that of the reactant A. Conversely, when the equilibrium constant is greater than unity, the velocity is more similar to that of the product B. The extent of zone-broadening and asymmetry at steady state is dependent upon the equilibrium constant, the characteristic reaction lifetime, and the electrophoretic mobility difference between reacting molecules. If all other parameters are held constant, the plate height is greatest and skew is least when the equilibrium constant is unity. The plate height increases linearly with the characteristic reaction lifetime and electrophoretic mobility difference, whereas the skew is independent of these parameters. These conclusions have important implications for the elucidation of thermodynamic and kinetic information from experimental data.     

毛细管电泳分离几种神经递质的研究

研究了不同毛细管预处理方法对组胺、5-羟色胺及儿茶酚胺类神经递质电泳分离的影响，采用优化的毛细管预处理方法及电泳分离条件基线分离了组胺、5-羟色胺、去甲肾上腺素和肾上腺素。利用多巴胺和5-羟色胺在毛细管内壁吸附效应的不同，对电泳淌度极为相近的多巴胺和5-羟色胺进行了分离和鉴定。以PC22细胞为研究对象，证实了该细胞中所含大量神经递质是多巴胺，不是5-羟色胺。     

糖类物质的毛细管电泳分析

毛细管电泳(CE)是近二十年发展起来的一种新的分离分析技术，它以快速、高效、高灵敏度、所需样品少等优点被广泛应用于各个领域。八十年代末开始应用于糖类物质的分析，并获得了快速发展。本文对毛细管电泳分离分析糖类物质进行了评述，主要集中在多糖的水解、衍生、检测、分析应用及前景等方面。全文引用文献40篇。