毛细管电泳-荧光/非接触电导组合型检测器的研制

报道了一种毛细管电泳-荧光／非接触电导组合型检测器。该检测器共用非接触电导检测池,实现了双检测器响应同步。优化了非接触电导检测系统中激发电压信号及其频率;荧光检测是用发光二极管作为激发光源,用光纤收集并传输荧光信号至光电倍增管。用无机金属离子和异硫氰酸荧光素评价该体系,结果表明,该检测器达到了任一单类型检测器性能指标。     

多通道非接触电导检测装置用于自由流电泳分离在线检测

现有自由流电泳(FFE)装置因不具备在线检测功能,其实用性仍然存在明显不足.针对这一问题,该工作发展了一种多通道电容耦合式非接触电导检测(MC-C4 D)装置并开发了自动测量软件.MC-C4 D装置采用了并行分时的非接触电导检测技术,即由多个同样的非接触电导检测模块并行排列,而单个电导检测模块又由多个非接触电导检测池组...     

新型微型电导池的研制及共地效应的消除

使用简便的方法制作了电极面积大、无死体积、分辨率高、检测限低的微型电导池;较好地消除了毛细管电泳(CE)在柱电导检测装置中存在的共地效应,排除了在线检测时高压分离回路对电导检测回路的干扰.并对制作的微型电导池的性能进行了测试.     

毛细管的交流阻抗特性研究

采用交流阻抗法研究了电容耦合非接触电导检测池毛细管的阻抗特性,分别考察了电极连接方式和毛细管内径对检测池阻抗的影响.实验表明:高频时,除去毛细管外层保护层会使检测池的阻抗减小,有助于检测器灵敏度的提高;采用铜箔作电极能够有效地消除电极与毛细管壁之间的空隙,使得检测池在低频时阻抗减小.随着毛细管内径的变大,阻抗依次减小.通过Zview软件拟合,提出的简单的拟合等效电路为R(RC)CPE.     

新型微型电导池的研制及其地效应的消除

使用简便的方法制作了电极面积大、无死体积、分辨率高、检测限低的微型电导池;较好地消除了毛细管电泳ＣＥ）在柱 存在的共地效应,排除了在线检测时高压分离回路对电导检测回路的干扰。并对制作的躲开电导池的性能进行了测试。     

多材料3D打印技术制作用于毛细管电泳的非接触电导/激光诱导荧光二合一检测池

利用多材料3D打印技术研制了用于毛细管电泳(CE)的二合一检测池,实现了电容耦合非接触电导(C4D)与共聚焦激光诱导荧光(LIF)两种检测方法在毛细管柱上同一位置同时检测.3D打印的检测池采用了导电的复合聚乳酸(PLA)材料制作C4 D的屏蔽层,采用普通的绝缘PLA材料支撑C4 D金属管电极并隔离屏蔽层.两根金属管电极...     

JONES型电导池测量的LCR电桥等效电路选择

JONES电导池系统的交流阻抗由电极过程的相关阻抗和电极间溶液的电阻两部分组成,可用适当的等效电路模拟。采用LCR电桥测量JONES电导池中溶液的电阻时需要选择合适的等效电路为模型解析测量的交流阻抗。通过等效电路的分析发现,选择串联电路作为LCR电桥的解析等效电路测量JONES型电导池中溶液的电阻时引入的误差比并联电路小。     

一种新型毛细管电泳双圆盘电极电导检测池

研制厂一种新型双凼盘电极毛细管电泳电导检测池。从理论和实验上分析验证了电导池参数、电导池位置对检测器性能的影响该检测池不仅结构简单、易于制作，而且极大地减小了柱外区带展宽，消除了高电压对检测器的影响，获得了较高的分离效率和信噪比采用Li^＋、Na^＋、K^＋的混合物对该检测池的性能进行了测试在最佳实验条件下，其俭出限分别为5．1、3．9和2．3μmol／L。     

微流控芯片非接触电导检测的研究进展

微流控芯片是一种现代分析新方法,非接触电导检测作为其重要检测技术之一,近年在仪器研制和应用等方面都取得了可喜的进展。本文重点对微流控芯片非接触电导检测的影响因素和应用的研究进展进行总结和评述。引用文献56篇。     

毛细管电泳非接触电导检测技术的新发展

毛细管电泳非接触电导检测(CE-CCD)是近年来发展迅速的一种检测技术。本文介绍了非接触式电导检测(CCD)的发展概况,着重阐述了CCD的原理、组成及应用情况。     

Raman spectra of dipicolinic acid in crystalline and liquid environments

Raman spectra of dipicolinic acid (DPA) are important for detection of bacterial spores, since DPA and its salts present one of their major components. The implementation of a deeply cooled CCD camera in combination with pulsed excitation at 532 nm allowed measuring well-resolved Raman spectra of the DPA in different forms. Powder preparations, crystals grown from saturated solutions and aqueous solutions of the DPA were studied. The spectral features in different environments and comparison with the spectra obtained by other methods are discussed.     

Miniaturized liquid core waveguide-based fluorimetric detection cell for capillary separation methods: application in CE of amino acids

A miniaturized post-column fluorimetric detection cell for capillary separation methods based on optical fibers and liquid core waveguides (LCWs) is described. The main part of the detection cell is a fused-silica capillary coated with Teflon AF serving as an LCW. The optical fibers are used both for coupling the excitation source with the detection domain in the LCW and for the axial fluorescence collection from the LCW end. The latter fiber is connected with a compact CCD spectrometer that serves for the rejection of the scattered excitation light and for the fluorescence signal detection. The proposed design offers a compact fluorescence detector for various microcolumn separation techniques without optical elements such as filters or objectives. Moreover, its construction and optical adjustment are very simple and the whole system is highly miniaturized. The function of the detection cell is demonstrated by CE of amino acids labelled by fluorescein-based tags. Separations of different standard amino acid mixtures and plasma samples are presented. The comparison of plasma amino acid levels of individuals being in good health with those of patients with inherited metabolic disorders is also shown.     

An integrated enzyme-linked immunosorbent assay system with an organic light-emitting diode and a charge-coupled device for fluorescence detection

A fluorescence detection system for a microfluidic device using an organic light-emitting diode (OLED) as the excitation light source and a charge-coupled device (CCD) as the photo detector was developed. The OLED was fabricated on a glass plate by photolithography and a vacuum deposition technique. The OLED produced a green luminescence with a peak emission at 512 nm and a half bandwidth of 55 nm. The maximum external quantum efficiency of the OLED was 7.2%. The emission intensity of the OLED at 10 mA/cm(2) was 13 μW (1.7 mW/cm(2)). The fluorescence detection system consisted of the OLED device, two band-pass filters, a five microchannel poly(dimethylsiloxane) (PDMS) microfluidic device and a linear CCD. The fluorescence detection system was successfully used in a flow-based enzyme-linked immunosorbent assay on a PDMS microfluidic device for the rapid determination of immunoglobulin A (IgA), a marker for human stress. The detection limit (S/N=3) for IgA was 16.5 ng/mL, and the sensitivity was sufficient for evaluating stress. Compared with the conventional 96-well microtiter plate assay, the analysis time and the amounts of reagent and sample solutions could all be reduced.     

原子发射光谱法中信背浓度比的推导与应用

基于原子发射光谱信号强度与CCD积分时间和样品浓度之间的线性关系, 推导并提出一种信背浓度比(SBCR)的新概念, 建立了检出限与SBCR之间的关系. 基于合理假设推导出最大积分时间、 最大信背比和最大信背浓度比等表达式, 并通过实验对模型进行了验证. 最后使用SBCR表征了低功率ArMPT对Cu元素的激发能力, 使其检出限由13.1 ng/mL降低至2.8 ng/mL.     

Detection of trace amounts of Ni by laser-induced fluorescence in graphite furnace with intensified charge coupled device

A laser-induced fluorescence in graphite furnace (LIF-GF) set-up has been equipped with an intensified CCD detector (ICCD) that enables simultaneous multichannel detection of large wavelength regions. The main advantages of such a system in comparison with conventional photomultiplier detection are: simultaneous detection of several fluorescence wavelengths for easy characterization of excitation and fluorescence spectra and for an increase of the absolute sensitivity and spectral selectivity; simultaneous monitoring of background signals, such as those due to matrix interferences, blackbody radiation and scattered laser light; decrease of the susceptibility to radio-frequency pick-ups emitted from the pump laser due to the delayed read-out procedure; time-resolved studies of fluorescence spectra for improved elemental selectivity or for studies of atomization processes, and a possibility to perform two-dimensional imaging of height distributions of atomization and, in combination with an imaging spectrometer, diffusion processes in the furnace. The first work on LIF-GF with ICCD detection has been performed on Ni. The most sensitive and versatile excitation and detection wavelengths have been identified. Detection limits in water solutions by the LIF-GF technique have been improved by two orders of magnitude and are found to be 0.015 pg with ICCD and 0.01 pg using a photomultiplier at the most sensitive excitation and detection wavelengths. Nickel in concentrations has been detected in aqueous standard reference samples with sodium concentrations ranging from to % (riverine water and estuarine water) with good accuracy and precision. The Ni contents of standard riverine and estuarine water were determined to 1.00 ± 0.11 and 0.75 ± 0.07 ng/ml, respectively. The certified concentrations are 1.03 ± 0.10 and 0.743 ± 0.078 .     

Tumor Cell Detection Device Based on Surface Plasmon Resonance Imaging and Image Processing

A laboratory-made tumor cell detection device was fabricated based on both surface plasmon resonance imaging（SPRi） and image processing.In this device,a gravity-induced flow injection chip（gFIC） was exploited to replace a pump.Also two charge coupled devices（CCDs） were used to detect HepG2 cells by SPRi and image processing,respectively.The results of two CCDs are associated.Protein A was used to modify the sensing surface.The inlet angle was carefully adjusted for the device to get an enhanced image.In the test,the contrast among cell solutions at different concentrations can be easily distinguished.The other CCD using image processing can tell false-positive in some degree.This detection is label-free,real time,and precise.     

Lamp‐based wavelength‐resolved fluorescence detection for protein capillary electrophoresis: Setup and detector performance

A lamp‐based fluorescence detection (Flu) system for CE was extended with a wavelength‐resolved (WR) detector to allow recording of full protein emission spectra. WRFlu was achieved using a fluorescence cell that employs optical fibres to lead excitation light from a Xe‐Hg lamp to the capillary window and protein fluorescence emission to a spectrograph equipped with a CCD. A 280 nm band pass filter etc. together with a 300 nm short pass cut‐off filter was used for excitation. A capillary cartridge was modified to hold the detection cell in a commercial CE instrument enabling WRFlu in routine CE. The performance of the WRFlu detection was evaluated and optimised using lysozyme as model protein. Based on reference spectral data, a signal‐intensity adjustment was introduced to correct for transmission losses in the detector optics that occurred for lower protein emission wavelengths. CE‐WRFlu of lysozyme was performed using BGEs of 50 mM sodium phosphate (pH 6.5 or 3.0) and a charged‐polymer coated capillary. Using the 3‐D data set, signal averaging over time and emission‐wavelength intervals was carried out to improve the S/N of emission spectra and electropherograms. The detection limit for lysozyme was 21 nM, providing sufficient sensitivity to obtain spectral information on protein impurities.     

Imaging and detection technologies for image analysis in electrophoresis

Image capture is the first step of image analysis. There are two major devices for image capture in the field of electrophoresis. One is the charged-couple device (CCD) camera and the other is the scanner. Image capture technologies have shown great progress in recent years especially in the field of fluorescence detection and chemiluminescent detection. The direction of image analysis is high resolution, wide dynamic range and high density precision and this holds true for the CCD camera system. Various components in the CCD camera system suitable for high-sensitive fluorescence detection and chemiluminescent detection are explained. As an example, the LAS-1000plus camera system which has 1364 x 922 pixels and generates 14-bits image is introduced. Powerful cooling enables overnight exposure of chemiluminescence. Introduction of blue light-emitting diode (LED) as excitation light source improved safety to eyes. Two types of scanners for fluorescence detection and the specific characteristics are explained. There are mechanical scanning systems using confocal optics and optical scanning systems using light collecting guide optics. Deep focusing range and equal fluorescence intensity at various depth is a characteristic feature of light collecting guide optics.     

Extension of the application range of UV-absorbing organic solvents in capillary electrophoresis by the use of a contactless conductivity detector

A contactless conductivity detection (CCD) system is used for capillary zone electrophoresis (CZE) with non-aqueous solvents of the buffering background electrolyte, which exhibit strong UV absorbance below 230 nm. It is found that the CCD characteristics with such solvents (propylene carbonate, N,N-dimethylformamide and N.N-dimethylacetamide as examples) is the same as with aqueous solutions: the same signal and noise is obtained for a given electric conductance of the background electrolyte, independent of the kind of the solvent. Therefore CCD enables the extension of the application range to solvents with restricted use for common UV detection in CZE due to their unfavourable or even unfitting optical properties. The applicability of CCD is demonstrated by CZE of aliphatic ammonium compounds in these solvents.     

Considerations on contactless conductivity detection in capillary electrophoresis

Nearly all analyses by capillary electrophoresis (CE) are performed using optical detection, utilizing either absorbance or (laser-induced) fluorescence. Though adequate for many analytical problems, in a large number of cases, e.g., involving non-UV-absorbing compounds, these optical detection methods fall short. Indirect optical detection can then still provide an acceptable means of detection, however, with a strongly reduced sensitivity. During the past few years, contactless conductivity detection (CCD) has been presented as a valuable extension to optical detection techniques. It has been demonstrated that with CCD detection limits comparable, or even superior, to (indirect) optical detection can be obtained. Additionally, construction of the CCD around the CE capillary is straightforward and robust operation is easily obtained. Unfortunately, in the literature a large variety of designs and operating conditions for CCD were described. In this contribution, several important parameters of CCD are identified and their influence on, e.g., detectability and peak shape is described. An optimized setup based on a well-defined detection cell with three detection electrodes is presented. Additionally, simple and commercially available read-out electronics are described. The performance of the CCD-CE system was demonstrated for the analysis of peptides. Detection limits at the microM level were obtained in combination with good peak shapes and an overall good performance and stability.