共查询到20条相似文献,搜索用时 31 毫秒
1.
Wang J Pumera M Chatrathi MP Escarpa A Konrad R Griebel A Dörner W Löwe H 《Electrophoresis》2002,23(4):596-601
A fully disposable microanalytical device based on combination of poly(methylmethacrylate) (PMMA) capillary electrophoresis microchips and thick-film electrochemical detector strips is described. Variables influencing the separation efficiency and amperometric response, including separation voltage or detection potential are assessed and optimized. The versatility, simplicity and low-cost advantages of the new design are coupled to an attractive analytical performance, with good precision (relative standard deviation RSD = 1.68% for n = 10). Applicability for assays of mixtures of hydrazine, phenolic compounds, and catecholamines is demonstrated. Such coupling of low-cost PMMA-based microchips with thick-film electrochemical detectors holds great promise for mass production of single-use micrototal analytical systems. 相似文献
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《Electroanalysis》2005,17(21):1991-1994
The development and performance of an end‐column amperometric detection system integrated with disposable screen‐printed electrodes for capillary electrophoresis is presented. In this system, the electrode and capillary can be easily replaced and the capillary/electrode alignment procedure is straightforward. The use of easily replaceable screen‐printed electrodes offers a tremendous benefit for capillary electrophoresis applications requiring frequent replacement of the working electrode due to fouling. This simple and convenient system is very attractive for routine analyses by capillary electrophoresis with electrochemical detection. The separation and determination of uric acid in human urine is presented. 相似文献
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Natural iron concentrations in real water samples have been determined by thermal lensing as a high performance capillary electrophoresis detector. 1,10-Phenanthroline was used as a chromogenic reagent, which forms a stable complex with Fe(II) but not with Fe (III). The interferences by other cations can be neglected by a combination of this photometric technique with high performance capillary electrophoresis. Laser induced thermal lens spectroscopy is demonstrated as a new technique for the measurement of small absorbances in the picoliter detection volume of a capillary. A limit of detection of 36 nmol/L with a signal to noise ratio of 7?:?1 was achieved using a 75 μm fused silica capillary. 相似文献
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Matysik FM 《Electrophoresis》2002,23(3):400-407
Over the recent years considerable efforts have been directed to the design of powerful detector arrangements for capillary electrophoresis (CE). The analytical characteristics of the detector have a great influence on the overall analytical performance of CE investigations. The major detection methods in CE, such as UV-Vis absorbance, fluorescence, mass spectrometry and electrochemical detection, have successfully been adapted also to nonaqueous capillary electrophoresis (NACE). However, the different properties of organic solvent systems require some modification of detector concepts and design compared to aqueous CE. The advances of detector development and application in NACE are reported and discussed with emphasis on methodical aspects. 相似文献
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A novel method for the synchronization of separation and determination is described, in which a mode-filtered light detector is used as an online detector in capillary electrophoresis. An instrument is described which has been developed for this purpose. The round capillary used in conventional capillary electrophoresis is replaced by an annular column, which is constructed from a naked optical fibre inserted into a fused-silica capillary. In fact, the annular electrophoresis column itself forms part of the mode-filtered light sensor. Along the side of the annular column are several detection channels for gathering and transmitting the mode-filtered light to a charge-coupled device (CCD). Every channel provides information on the sample from the point at which it is located. Using capillary isotachophoresis incorporating the annular column, the analytes in a sample containing alanine (10.0 mM) and glycine (9.7 mM) were simultaneously separated and determined using multichannel mode-filtered light detection with a detection limit of 1.5 mM. 相似文献
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Mario Castaño-Álvarez Agustín Costa-García María Agirregabiria Jesús Miguel Ruano-López 《Talanta》2009,80(1):24-34
A new SU-8 based microchip capillary electrophoresis (MCE) device has been developed for the first time with integrated electrochemical detection. Embedded electrophoretic microchannels have been fabricated with a multilayer technology based on bonding and releasing steps of stacked SU-8 films. This technology has allowed the monolithic integration in the device of the electrochemical detection system based on platinum electrodes. The fabrication of the chips presented in this work is totally compatible with reel-to-reel techniques, which guarantee a low cost and high reliability production. The influence of relevant experimental variables, such as the separation voltage and detection potential, has been studied on the SU-8 microchip with an attractive analytical performance. Thus, the effective electrical isolation of the end-channel amperometric detector has been also demonstrated. The good performance of the SU-8 device has been proven for separation and detection of the neurotransmitters, dopamine (DA) and epinephrine (EP). High efficiency (30,000-80,000 N/m), excellent precision, good detection limit (450 nM) and resolution (0.90-1.30) has been achieved on the SU-8 microchip. These SU-8 devices have shown a better performance than commercial Topas (thermoplastic olefin polymer of amorphous structure) microchips. The low cost and versatile SU-8 microchip with integrated platinum film electrochemical detector holds great promise for high-volume production of disposable microfluidic analytical devices. 相似文献
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This report describes the development and application of a novel graphene/poly(methyl methacrylate) composite electrode as a sensitive amperometric detector of capillary electrophoresis. The composite electrode was fabricated on the basis of the in situ polymerization of a mixture of graphene and prepolymerized methyl methacrylate in the microchannel of a piece of fused silica capillary under heat. SEM, XRD and FT-IR offered insights into the nature of the composite. The results indicated that graphenes were well dispersed in the composite to form an interconnected conducting network. The performance of this unique graphene-based detector has been demonstrated by separating and detecting seven naturally occurring phenolic compounds in Herba Geranii in combination with capillary electrophoresis. The graphene-based detector offered significantly lower operating potentials, substantially enhanced signal-to-noise characteristics, and lower expense of operation. The simplicity and significant performance exhibited by the graphene/poly(methyl methacrylate) composite electrode also indicate great promise for microchip CE, flowing injection analysis, and other microfluidic analysis systems. 相似文献
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A simplified poly(dimethylsiloxane) capillary electrophoresis microchip integrated with a low-noise contactless conductivity detector 总被引:1,自引:0,他引:1
A contactless conductivity detector integrated into a poly(dimethylsiloxane) microchip for electrophoresis is presented. It adopted the simplest configuration of electrodes commonly used in this detection mode for capillary electrophoresis microchips. Although the chip is based on a simple and effective design, it is able to obtain low detection levels due to the low noise of the detection circuit. A circuit based on a lock-in amplifier was designed on printed circuit boards to read out the signal. The property of the detection cell was studied by applying excitation signals of different frequencies and different amplitudes. It was found that the best detection limit could be achieved with a frequency of 50?kHz and amplitude of 20?V. The performance of the detector was demonstrated by successfully separating and detecting several inorganic ions and also a mixture of heavy metal ions. An average detection limit of 0.4?μM was obtained for inorganic cations. This value is significantly improved compared to similar microchip-based detectors. The presented detector could be promising for mass production due to its properties, such as simple construction, high degree of integration, high performance and low cost. 相似文献
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介绍了电容耦合非接触电导检测(C4D)的检测原理及其最新的研究进展,引用文献50篇。C4D是近几年发展起来的一种用于毛细管电泳和微流控芯片电泳的新检测技术。C4D检测器的原理清楚,结构简单,易于微型化、集成化,不污染检测电极,因而很有应用价值。 相似文献
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A new laser-induced fluorescence (LIF) detector for multicapillary electrophoresis is presented. The detection principle is based on waveguiding of the emitted fluorescence from the point of illumination to the capillary ends by total internal reflection (TIR) and imaging of the capillary ends. The capillaries themselves thus act as liquid core waveguides (LCWs). At the illumination point, the capillaries are arranged in a planar array, which allows clean and efficient illumination with a line-focused laser beam. The capillary ends are rearranged into a small, densely packed two-dimensional array, which is imaged end-on with high light collection efficiency and excellent image quality. Wavelength dispersion is obtained with a single prism. Intercapillary optical crosstalk is less than 0.5%, and rejection of stray light is very efficient. The detector is applied to four-color DNA sequencing by gel electrophoresis in a 91-capillary array, with simple fluorescein and rhodamine dyes as fluorophores. Since the imaged two-dimensional array is so compact, the detector has a high potential for very large-scale multiplexing. 相似文献
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N A Guzman J Moschera C A Bailey K Iqbal A W Malick 《Journal of chromatography. A》1992,598(1):123-131
A method is described to enhance the resolution and detection sensitivity of proteins, peptides, and amino acids in capillary electrophoretic analysis of solution mixtures. The method consists of derivatizing the analytes with fluorescamine, which is normally used as a fluorogenic reagent for compounds containing a reactive primary amine functional group, and then using the derivative as an ultraviolet chromophore to enhance detection sensitivity (measured at 280 nm) in capillary electrophoresis. The results demonstrated a significant improvement in the separation and detection sensitivity of the derivatized analytes as compared to their underivatized counterparts. The use of chromophores, such as fluorescamine, in capillary electrophoresis facilitates the analysis of components of solution mixtures, such as pharmaceutical formulations, that could not be resolved and/or detected by conventional capillary electrophoresis procedures. 相似文献
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一种基于双工作电极-双通道的毛细管电泳电化学检测系统 总被引:2,自引:0,他引:2
报道了一种双工作电极-双通道毛细管电泳电化学检测系统,实现电导和安培 同时检测或者安培与安培检测联用,使两种方法相互补充,发挥各自的优势。其中 ,工作电极与检测池的制作工艺简单,操作简便,通过不锈钢针管和毛细管作为套 管,无需三维微调装置即可简单实现双工作电极的准确放置及分离毛细管与工作电 极的准确对接,并根据分析体系的需要采用不同类型的工作电极和检测器;同时采 用复式滤波电路解决了不同检测器之间的电场叠加对输出信号的干扰问题。采用该 装置可以同时检测复杂体系中的电活性和惰性物质,或同时测定只能氧化或只能还 原的物质,还可以对具有氧化还原性质的物质进行纯度的确证。将该装置应用于实 际样品的测定,节约了分析时间,提高了分析速度,扩大了检测范围,结果令人满 意。 相似文献
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BingYiYANG JinYuanMO RongLAI 《中国化学快报》2004,15(4):439-442
A new type of dual-electrode and multi-channel electrochemical detection technology for capillary electrophoresis is described in this paper.Two detectors(the amperometric detector and the conductometric detector) or two conductometric detectors are connected to the same capillary electrophoresis system.The whole system possesses the advantages of the two electrochemical detectors including sparing time,improving the analytical speed and expanding the sample range.The working electrode and detector cell are handled easily.The system was applied to sample detection with satisfactory results. 相似文献
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On-line microwave-induced helium plasma atomic emission detection for capillary zone electrophoresis
We report a feasibility study on using a microwave-induced helium plasma atomic emission detector (MIP-AED) as an on-line detector in capillary zone electrophoresis (CZE). To couple CZE to MIP-AED, we used an ion exchange membrane capillary to connect the separation capillary to the interfacing capillary. The outlet end of the interfacing capillary was placed directly in the discharge tube of the MIP-AED system. The electroosmotic flow generated in the separation capillary carried the analytes and the electrolyte buffer solution through the interfacing capillary into the MIP-AED discharge tube where the analytes were detected. The performance of the CZE/MIP-AED system was evaluated with trimethyltin chloride, dimethyltin dichloride, n-propanol, and 2-butanone. The preliminary results indicate that the MIP-AED can be used in CZE to provide element-specific detection for target analytes. 相似文献
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A simple analytical system using disposable, open-tubular ion exchange clean-up precolumns coupled in-line to capillary electrophoresis for direct injection of biological samples is presented. The clean-up precolumns were prepared from fused silica capillaries by thermally initiated layer-by-layer polymerization of poly(butadiene-maleic acid) (PBMA) directly on the capillary wall. Typically, 6 cm long precolumns with 4-layers of PBMA were used for sample pretreatment. A robust and reproducible coupling between the precolumn (75 μm ID) and the analytical capillary (50 μm ID) was achieved using an inexpensive, commercially available low dead volume union. No extra dispersion of the analyte zones was observed. Proteins and other high molecular weight compounds from biological sample matrices were retained on the cation-exchanger sites of the precolumn, which eliminated their adsorption on analytical capillary walls and ensured stable electroosmotic flow and migration times of target analytes. Unretained small inorganic cations migrated freely into the analytical capillary for separation and detection. Applicability of the sample clean-up procedure was proved by determination of major inorganic cations in blood serum and plasma samples using capillary electrophoresis with contactless conductivity detection. Separations were performed in background electrolyte solution consisting of 15 mM L-arginine, 12.5 mM maleic acid, 3 mM 18-crown-6 at pH 5.5 and repeatabilities of migration times and peak areas were below 1.5% and 7.3%, respectively. Less than 1 μL of biological sample was required for injection. 相似文献