毛细管电泳中的毛细管区段灌注及其相关技术

毛细管区段灌注是一种随手性毛细管电泳、亲和毛细管电泳和胶束电动力色谱-质谱发展而产生的实验技术。由于它能消除采用以上方法时遇到的缓冲溶液对检测的影响。因此引起人们的关注。本文对区段灌注技术的原理,区段灌注技术在手性毛细管电泳、亲和毛细管电泳和胶束电动力色谱中的应用,以及目前区段灌注技术存在的一些问题进行了评述。本文还对由区段灌注技术发展而来的逆流毛细管电泳、液相预柱毛细管电泳、多步配体进样等实验技术进行了简介。     

聚乙二醇共价修饰药用蛋白质的分析方法

聚乙二醇共价修饰蛋白质具有重要的生物学应用意义。分析聚乙二醇共价修饰蛋白质对确定产物的修饰程度是必要的,近年来渐成研究热点。主要介绍了聚乙二醇共价修饰蛋白质的各种分析方法与其优缺点。同时对不同原理的分析方法进行了分类比较。     

糖胺聚糖分析测定的研究进展

糖胺聚糖是一类重要的生物大分子。综述了利用分子光谱法、高效液相色谱法、电泳法、质谱法和电化学等方法对其进行分析测定的研究进展。     

Rapid determination of protein binding constant by a pressure-mediated affinity capillary electrophoresis method

A new pressure-mediated affinity capillary electrophoresis method for the rapid and accurate determination of drug-protein binding constants is described. A special combination of pressure and electrophoresis is used to shorten the electrophoresis and the overall analysis time to only a few minutes. At the same time, the suitability of this method is checked against a traditional fluorescence spectroscopy method. The binding constants of bovine serum albumin and a total of eight drugs with different pK(a) have been evaluated and compared with those determined by the fluorescence spectroscopy method and other methods in literature. The results indicate that the P-ACE method is well suited for the determination of binding constants with weak interaction (K(b) <10(5) M(-1)).     

Speciation of oxidation states of elements by capillary electrophoresis

Progress made in the last five years in the application of capillary electrophoresis methods to chemical speciation of elements is reported on the basis of over 100 literature references. The main trends observed include development of new on‐ and off‐capillary derivatization methods, application of new detection methods, and especially coupling of CE separation systems to powerful atomic spectroscopy and mass spectrometry instruments with various ionization techniques, providing either a sensitive element‐specific detection method or a third dimension for high performance separation. Besides numerous CZE and MEKC capillary electrophoresis methods only very few examples of CE speciation with capillary electrochromatography can be found. Concerning the chemical forms of elements determined, the new procedures developed are mostly focused on redox speciation of various oxidation states of elements, metal‐bound high molecular compounds, and organometallic species.     

Determination of tea catechins

An overview of analytical methods for the measurement of biologically important tea catechins is presented. Liquid chromatography and capillary electrophoresis are the most cited techniques for catechin separation, identification and quantitation. Liquid chromatography with ultraviolet detection is frequently used; however, mass spectrometry, electrochemical, fluorescence and chemiluminescence detection are also utilized in cases where more sensitive or selective detection is needed. Two modes of capillary electrophoresis, capillary zone electrophoresis and micellar electrokinetic capillary chromatography, have been employed for the determination of catechins. Both modes of capillary electrophoresis are based on ultraviolet detection. Additional analytical techniques, such as gas chromatography, thin-layer chromatography, paper chromatography, spectrophotometry, biosensing, chemiluminescence and nuclear magnetic resonance spectroscopy have also been utilized for the determination of catechins and are reviewed herein.     

A fluorescence toolbox: A review of investigation of electrophoretic separations,process, and interfaces

This review focuses on fluorescence spectroscopy techniques for the investigation of electrophoretic separations. Fluorescence has been used as a sensitive detector for capillary, gel, and microchip electrophoresis for decades. However, advanced fluorescence methods can be used to study transport, interfacial phenomena, intermolecular and affinity interactions, and other processes that occur during separation. This so‐called spectroscopic toolkit can be implemented to understand fundamental behavior in electrophoresis and electrokinetic chromatography. Techniques such as fluorescence recovery after photobleaching, fluorescence correlation spectroscopy, and fluorescence anisotropy are discussed in relation to electrophoretic separations. Newer methods such as super‐resolution microscope are also introduced.     

Hyphenated chromatographic methods for biomaterials

The improvement in hyphenated analytical techniques has significantly widened their applications to the analysis of biomaterials. In this article, we discuss recent advances in applications of hyphenated chromatographic techniques including capillary electrophoresis to the analyses of biological samples. As tools of separation, gas chromatography, high-performance liquid chromatography and capillary electrophoresis are considered with special emphasis on applications utilizing the hyphenation of these methods to mass spectrometry. Moreover, applications using other detection methods such as Fourier transform infrared spectroscopy hyphenated to gas chromatography and photodiode array detector combined with high-performance liquid chromatography or capillary electrophoresis are also discussed. Owing to their high sensitivity, luminescence-based detection systems such as laser-induced fluorescence and chemiluminescence are also included in this review.     

毛细管区带电泳法测定3种香豆素的离解常数

采用毛细管区带电泳法(CZE)测定瑞香苷(DN)、瑞香素(DP)和7-羟基香豆素(7-HC)的离解常数(p Ka).通过测试不同酸度条件下各香豆素的迁移时间,以香豆素在电泳中有效淌度和运行液中OH-浓度的关系,推导了毛细管区带电泳-紫外分光光度(CZE-UV)法测定3种香豆素离解常数(p Ka)的线性模型,并建立了这3种香豆素的p Ka测定方法.测得3种香豆素的p Ka值分别是7.43(7-HC)、6.91(DN)和6.86(DP).同时也采用传统方法 -紫外分光光度法对这些物质的p Ka进行测定以验证CZE的可靠性,两种测定结果相一致,说明CZE-UV法用于3种香豆素的离解常数的测定,快速、简便、结果可靠.     

Stereolabile chiral compounds: analysis by dynamic chromatography and stopped-flow methods

Enantiomerization and diastereomerization reactions of chiral compounds play a major role in all aspects of chemistry spanning a wide bridge from drug development to supramolecular chemistry. Traditionally, these reactions are studied by variable-temperature NMR spectroscopy and chiroptical methods such as polarimetry. However, powerful complimentary methods based on chromatography and electrophoresis have been developed and applied to a variety of stereolabile chiral compounds. This tutorial review explains the principles, applications, and limitations of dynamic chromatography and chromatographic and electrophoretic stopped-flow analysis for the investigation of isomerization reactions of chiral compounds.     

Competitive adsorption

A review is presented on the multicomponent competitive adsorption, static equilibrium adsorption, and dynamic nonequilibrium adsorption from gaseous and liquid media onto the surface of porous and disperse solids. The state of the theory of multicomponent adsorption is analyzed. Not only traditional methods were used for investigations in this field but also NMR spectroscopy (difference in the spectra of adsorbed and free compounds), FTIR spectroscopy (difference in the spectra of surface groups and bonds in adsorbates), calorimetry, thermally stimulated depolarization, photon correlation spectroscopy, electrophoresis, and cryoporometry. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 43, No. 3, pp. 133–169, May–June, 2007.     

Techniques for the analysis of pentacyclic triterpenoids in medicinal plants

Triterpenes are a major class of chemical compounds found in natural plants and can be categorized into acyclic triterpenoids, monocyclic triterpenoids, tricyclic triterpenoids, tetracyclic triterpenoids, and pentacyclic triterpenoids. Among them, pentacyclic triterpenoids have gained more extensive attention due to their biological activities, including anti‐inflammation, antibacterial, antioxidation, antitumor, anti‐HIV, hepatoprotection, and immunological adjuvant properties. In this review, we summarize the extraction and analytical methods for pentacyclic triterpenoids, where more than 56 triterpenes from 49 kinds of plants were involved. The analysis methods include gas chromatography, liquid chromatography, capillary electrophoresis, thin‐layer chromatography, supercritical fluid chromatography, NMR spectroscopy, and X‐ray spectroscopy. This review provides valuable reference for the determination of pentacyclic triterpenoids in medicinal plants.     

Review on recent advances in the analysis of isolated organelles

The analysis of isolated organelles is one of the pillars of modern bioanalytical chemistry. This review describes recent developments on the isolation and characterization of isolated organelles both from living organisms and cell cultures. Salient reports on methods to release organelles focused on reproducibility and yield, membrane isolation, and integrated devices for organelle release. New developments on organelle fractionation after their isolation were on the topics of centrifugation, immunocapture, free flow electrophoresis, flow field-flow fractionation, fluorescence activated organelle sorting, laser capture microdissection, and dielectrophoresis. New concepts on characterization of isolated organelles included atomic force microscopy, optical tweezers combined with Raman spectroscopy, organelle sensors, flow cytometry, capillary electrophoresis, and microfluidic devices.     

阿霉素─铁(Ⅲ)配合物的电化学特征及其与DNA结合作用研究

采用示波极谱法和循环伏安法研究了3公铁离子Fe(Ⅲ)与阿霉素(ADM)配合物的电化学特性.在生理pH条件下,Fe(Ⅲ)与ADM形成2：1的稳定配合物,Fe(Ⅲ)的配位使ADM在更负的电势下才能还原,这与其心脏毒性减轻密切相关.采用线性扫描、吸收光谱和凝胶电泳法研究了ADM－Fe(Ⅲ)配合物与DNA的结合作用,ADM－Fe(Ⅲ)配合物仍保留了ADM插入结合的特征,并形成一种稳定的DNA－Fe(Ⅲ)－ADM的三元结合物.     

Improvements in pentosan polysulfate sodium quality assurance using fingerprint electropherograms

Complex samples from polymer production, plant extracts or biotechnology mixtures can be characterized by fingerprints. Currently, the standard approach for sample characterization employs near-infrared (NIR) spectroscopy fingerprinting. Up to now, however, fingerprints obtained by chromatography or electrophoresis could only be visually evaluated. This type of inspection is very labor-intensive and difficult to validate. In order to transfer the use of fingerprints from spectroscopy to electrophoresis, spectra-like properties must be obtained through a complete alignment of the electropherograms. This has been achieved by interpolation and wavelet filtering of the baseline signal in the present work. The resulting data have been classified by several algorithms. The methods under survey include self-organizing maps (SOMs), artificial neural networks (ANNs), soft independent modeling of class analogy (SIMCA) and k-nearest neighbors (KNNs). In order to test the performance of this combined approach in practice, it was applied to the quality assurance of pentosan polysulfate (PPS). A recently developed capillary electrophoresis (CE) method using indirect UV detection was employed in these studies [1]. All algorithms were well capable of classifying the examined PPS test batches. Even minor variations in the PPS composition, not perceptible by visual inspection, could be automatically detected. The whole method has been validated by classifying various (n = 400) unknown PPS quality assurance samples, which have been correctly identified without exception.     

Speciation of metal ions in proteins by combining PIXE and thin layer electrophoresis

Particle induced X-ray emission (PIXE) spectroscopy is a simple and convenient method of quantitative multielemental analysis with sensitivities in the μg/g range, that can be successfully used for trace analysis of metal ions in proteins or enzymes. However, due to its elemental character the technique alone is not a priori suitable for speciation. Keeping track of the metal ions of interest throughout a proper biochemical separation technique, on the other hand, could be a useful strategy for speciation. Different versions of thin layer electrophoresis (polyacrylamide gel, agarose or cellulose acetate electrophoresis) are very effective and sensitive methods to separate proteins or protein fragments. Due to the high absolute sensitivity of PIXE the metal ions concentrated in the narrow bands of an electropherogram can be in situ successfully detected. The present paper describes this unique combination of biochemical separation and ion beam analysis which significantly extends the information obtained from electrophoresis. Illustrative applications are given and the advantages and limitations of the method are discussed. Possible extensions of the technique are also outlined.     

cis/trans photoisomerization of secondary thiopeptide bonds

The reversible cis/trans photoisomerization of secondary thiopeptide bonds has been systematically studied with UV-visible absorption, capillary electrophoresis, 1H NMR spectroscopy, and circular dichroism methods. It was found that the concentration of the cis conformers could be increased from less than 1 % in the thermal equilibrated solution to up to 20 % in the photostationary state. The rotational barriers of the thiopeptide bond and the pH dependence of the isomerization rates were also studied. The quantum yields of the trans-->cis and the cis-->trans processes were determined from photokinetic analysis.     

Fabrication of calcium fluoride capillary electrophoresis microdevices for on-chip infrared detection

In this paper, we demonstrate microfluidic capillary electrophoresis (CE) devices made in CaF2 , for optical detection in a broad spectral range. We have designed methods for micromachining and enclosing capillaries in CaF2. The utility of these microdevices has been shown through CE analysis of fluorescently labeled amino acids. We have also performed infrared spectroscopy for analyte identification in microfluidic CaF2 channels. These CaF2 microdevices open the door to microchip separations with optical detection in the ultraviolet, visible, and infrared spectral regions.     

Determination of Dipeptidyl Peptidase-4 Inhibitors by Spectrophotometric and Chromatographic Methods

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a novel class of oral anti-diabetic agents used in the treatment of type 2 diabetes mellitus and work to enhance the effect of incretin hormones. There has been significant research on wide range of analytical techniques that could be useful in the estimation of DPP-4 inhibitors in formulations and biological matrices. Analytical methods such as ultraviolet (UV) spectrophotometry, mass spectroscopy, NMR spectroscopy, HPLC, high pressure thin layer chromatography, ultra performance liquid chromatography, liquid chromatography?mass spectrophotometry and capillary zone electrophoresis have been reported for the estimation of DPP-4 inhibitors in single and/or in combination with other drugs. This comprehensive review covers most of the spectrophotometric and chromatographic methods described for the determination of sitagliptin, alogliptin, vildagliptin, linagliptin, saxagliptin and teneligliptin in pure forms, in different pharmaceutical dosage forms and biological fluids. From the review it can be deduced that a large number of chromatographic methods have been developed, and HPLC-UV methods have been commonly used in the detection and evaluation of DPP-4 inhibitors.     

Analytical devices based on light-emitting diodes – a review of the state-of-the-art

A general overview of the development of the uses of light-emitting diodes in analytical instrumentation is given. Fundamental aspects of light-emitting diodes, as far as relevant for this usage, are covered in the first part. The measurement of light intensity is also discussed, as this is an essential part of any device based on light-emitting diodes as well. In the second part, applications are discussed, which cover liquid and gas-phase absorbance measurements, flow-through detectors for chromatography and capillary electrophoresis, sensors, as well as some less often reported methods such as photoacoustic spectroscopy.