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本文综述了微型计算机发展起来后在各种滴定中的应用。文内将应用微型计算机的自动滴定系统分成三个部分:滴定装置、检测装置和计算机控制部分,分别介绍了它们的发展,现状和应用情况,列举了系统对各部分的要求,对联机系统与脱机系统、高级语言与机器语言控制,以及几种常见的数据处理方法进行了比较。 相似文献
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电化学检测池的结构与装置 LCEC系统可以简化成图1。一般由四部分组成:样品注入、溶剂传输、色谱分离和电化学检测。本文将主要介绍LCEC仪器中的电分析化学原理。由于电分析检测方法种类繁多,电解池装置(包括电极材料、形状及电解池结构等)的设计也有相当的数量。我们将试图对LCEC系统中电极材料的选择和电解池结构的设计等的一般性原则作出总结。 相似文献
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基于分子印迹膜的检测牛奶中琥珀酸氯霉素残留传感方法的研究 总被引:6,自引:2,他引:4
采用光聚合法在一次性丝网印刷电极上制备琥珀酸氯霉素分子印迹膜,然后将丝网印刷电极通过电极插口与电化学分析装置相连接,组装成检测琥珀酸氯霉素残留的电化学传感仪.使用与传感装置相连接的记录仪记录响应的结果.采用本传感仪建立了检测氯霉素的标准曲线并测试了实际牛奶样品中氯霉素含量.电镜学观察表明,与非印迹膜相比,在印迹膜表面形成大量直径约为100 nm的印迹微孔.本传感仪装置检测琥珀酸氯霉素具有很高的灵敏度和特异性,检出限为2×10-9 mol/L,检测线性范围为1×10-8~1.2×10-5 mol/L,基于牛奶样品的检测回收率介于93.5%~95.5%之间. 相似文献
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本研究组设计了SPR现场监测MIFs热聚合成膜过程的装置, 并对所制备MIFs的吸附特性进行了检测. 相似文献
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描述了一种激光诱导荧光检测装置。该装置的核心是由低折射率的聚四氟乙烯空心管和流动水溶液构成的液芯光纤,激光作为激发光垂直的照射液芯光纤,光纤内的荧光物质产生的发射光在液芯光纤内发生反射。CCD检测器在液芯光纤的一端对发射光进行检测。应用该装置利用Cu离子催化H2O2氧化罗丹明B(Rh B)造成荧光猝灭对Cu2 进行检测。在线性范围0.4~4μg/L内得到的检出限为0.022μg/L。该方法具有较高的灵敏度,重要原因是CCD的检测消除了液芯光纤中散射的激光的干扰。相比于昂贵的商业荧光仪,本装置能得出更好的检测结果。 相似文献
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In this study, a new design of a controllable micro-lens structure capable of the enhancement of LIF detection system has been demonstrated, which can be further integrated with buried optical fibers on a micro-CE chip for sample separation and detection. Two pneumatic side-chambers were placed between a micro-CE channel and an optical fiber channel. The intervals between the side-chamber and the microchannel were used to form two surfaces of the controllable micro-lens structure. Deformations of the two surfaces can be generated after pressurized index-matching fluid was injected into the pneumatic side-chambers. The side-chambers can be deflected as a double convex lens to focus both the excitation light source and the fluorescent emission signal. The profile and the focal length of the micro-lens structure can be actively adjusted by applying different liquid pressures so that biosamples with a low concentration can be detected. Using low-cost polymeric materials such as polydimethylsiloxane, rapid and reliable fabrication techniques involving standard lithography and replication process was employed for the formation of the proposed chip device. Experimental results revealed the controllable micro-lens structure can be successfully deformed as a convex lens to focus the laser light source and the collected fluorescence signal can be enhanced accordingly. The power amplitude of excitation laser light can be enhanced by 5.4-fold. FITC dye and DNA markers were then utilized for micro-CE testing. The results indicated that the signal amplitude could be enhanced 2.5-fold when compared to the case without the activation of the micro-lens. According to the experimental results, the developed device has a great potential to be integrated with other microfluidic devices for further biomedical applications. 相似文献
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J. Kristóf J. Inczédy J. Paulik F. Paulik 《Journal of Thermal Analysis and Calorimetry》1979,15(1):151-157
A technique developed for the continuous and selective detection of water vapour formed during thermal decomposition reactions is described. The device can be connected to different types of thermoanalytical instruments without any difficulties. The detector can closely follow changes in the amount of water released during decomposition reactions, with negligible time delay. The signal curves obtained by the detector can be compared to the simultaneously recorded thermoanalytical curves and used to determine the step in which the water was released. The device as a free standing unit can be used to detect water plugs in different gas flows as well. 相似文献
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Sysoev A Adamov A Viidanoja J Ketola RA Kostiainen R Kotiaho T 《Rapid communications in mass spectrometry : RCM》2004,18(24):3131-3139
An ion mobility spectrometer that can easily be installed as an intermediate component between a commercial triple-quadrupole mass spectrometer and its original atmospheric pressure ionization (API) sources was developed. The curtain gas from the mass spectrometer is also used as the ion mobility spectrometer drift gas. The design of the ion mobility spectrometer allows reasonably fast installation (about 1 h), and thus the ion mobility spectrometer can be considered as an accessory of the mass spectrometer. The ion mobility spectrometer module can also be used as an independently operated device when equipped with a Faraday cup detector. The drift tube of the ion mobility spectrometer module consists of inlet, desolvation, drift, and extraction regions. The desolvation, drift and extraction regions are separated by ion gates. The inlet region has the shape of a stainless steel cup equipped with a small orifice. Ion mobility spectrometer drift gas is introduced through a curtain gas line from an original flange of the mass spectrometer. After passing through the drift tube, the drift gas serves as a curtain gas for the ion-sampling orifice of the ion mobility spectrometer before entering the ion source. Counterflow of the drift gas improves evaporation of the solvent from the electrosprayed sample. Drift gas is pumped away from the ion source through the original exhaust orifice of the ion source. Initial characterization of the ion mobility spectrometer device includes determination of resolving power values for a selected set of test compounds, separation of a simple mixture, and comparison of the sensitivity of the electrospray ionization ion mobility spectrometry/mass spectrometry (ESI-IMS/MS) mode with that of the ESI-MS mode. A resolving power of 80 was measured for 2,6-di-tert-butylpyridine in a 333 V/cm drift field at room temperature and with a 0.2 ms ion gate opening time. The resolving power was shown to be dependent on drift gas flow rate for all studied ion gate opening times. Resolving power improved as the drift gas flow increased, e.g. at a 0.5 ms gate opening time, a resolving power of 31 was obtained with a 0.65 L/min flow rate and 47 with a 1.3 L/min flow rate for tetrabutylammonium iodide. The measured limits of detection with ESI-MS and with ESI-IMS/MS modes were similar, demonstrating that signal losses in the IMS device are minimal when it is operated in a continuous flow mode. Based on these preliminary results, the IMS/MS instrument is anticipated to have potential for fast screening analysis that can be applied, for example, in environmental and drug analysis. 相似文献
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The occurrence of electrochemical processes during the operation of an electrospray ionization (ESI) source is well established. In the positive ion mode, electrons are drawn from the ESI metal capillary to a high voltage power supply. These electrons are the product of charge-balancing oxidation reactions taking place at the liquid/metal interface of the ion source. In a recent study, (Anal. Chem.2001, 73, 4836-4844), our group has shown that the introduction of a ground loop can dramatically enhance the rate of these oxidation processes. Such a ground loop can be introduced by connecting the sample infusion syringe (or the liquid chromatography column, in the case of LC-MS studies) to ground. The magnitude of the ground loop current can be controlled by the electrolyte concentration in the analyte solution, and by the dimensions of the capillary connecting the syringe needle and the ESI source. Using ferrocene as a model system, it is demonstrated that the introduction of such a ground loop can significantly enhance the signal intensity of analytes that form electrochemically ionized species during ESI. However, analytes that form protonated molecular ions, such as reserpine, also show higher signal intensities when a ground loop is introduced into the system. This latter observation is attributed to the occurrence of electrolytic solvent (acetonitrile and/or water) oxidation processes. These reactions generate protons within the ion source, and thus facilitate the formation of [M + nH](n+) ions. Overall, this work provides an example of how the careful control of electrochemical parameters can be exploited to optimize signal intensities in ESI-MS. 相似文献
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Dr. Paolo Bollella Dr. Inhee Lee Prof. David Blaauw Prof. Evgeny Katz 《Chemphyschem》2020,21(1):120-128
Biocatalytic buckypaper electrodes modified with pyrroloquinoline quinone (PQQ)-dependent glucose dehydrogenase and bilirubin oxidase for glucose oxidation and oxygen reduction, respectively, were prepared for their use in a biofuel cell. A small (millimeter-scale; 2×3×2 mm3) enzyme-based biofuel cell was tested in a model glucose-containing aqueous solution, in human serum, and as an implanted device in a living gray garden slug (Deroceras reticulatum), producing electrical power in the range of 2–10 μW (depending on the glucose source). A microelectronic temperature-sensing device equipped with a rechargeable supercapacitor, internal data memory and wireless data downloading capability was specifically designed for activation by the biofuel cell. The power management circuit in the device allowed the optimized use of the power provided by the biofuel cell dependent on the sensor operation activity. The whole system (power-producing biofuel cell and power-consuming sensor) operated autonomously by extracting electrical energy from the available environmental source, as exemplified by extracting power from the glucose-containing hemolymph (blood substituting biofluid) in the slug to power the complete temperature sensor system and read out data wirelessly. Other sensor systems operating autonomously in remote locations based on the concept illustrated here are envisaged for monitoring different environmental conditions or can be specially designed for homeland security applications, particularly in detecting bioterrorism threats. 相似文献
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Colas des Francs G Girard C Laroche T Lévèque G Martin OJ 《The Journal of chemical physics》2007,127(3):034701
The new optical concepts currently developed in the research field of plasmonics can have significant practical applications for integrated optical device miniaturization as well as for molecular sensing applications. Particularly, these new devices can offer interesting opportunities for optical addressing of quantum systems. In this article, we develop a realistic model able to explore the various functionalities of a plasmon device connected to a single fluorescing molecule. We show that this theoretical method provides a useful framework to understand how quantum and plasmonic entities interact in a small area. Thus, the fluorescence signal evolution from excitation control to relaxation control depending on the incident light power is clearly observed. 相似文献
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Development of a simplified densitometer for the determination of aflatoxins by thin-layer chromatography 总被引:3,自引:0,他引:3
A simple, miniaturised and low power consuming (battery, fully semiconductor based) detector cell (SeBaDeC) was developed for the densitometric measurement of aflatoxins on TLC plates. A UV-light emitting diode (UV-LED) with a peak emission wavelength of 370 nm was used for fluorescence excitation, while a photo diode with a peak sensitivity of 440 nm in combination with a 418 nm cut-off filter was applied for detecting the fluorescence intensity. The resulting signal was further amplified by means of a commonly used operational amplifier integrated circuit (OA) and directly converted into a digital signal with a simple analogue-digital-converter (ADC). This signal was recorded at the serial (RS232) port of a portable PC and processed with a spreadsheet program. The software used for data recording is freeware and available in its source code, and the long lifetime of the UV-LED (up to 10 000 h) permits a maintenance free application of this device. This simplified device has shown to be able to detect concentrations of aflatoxins of 1 ng, thus offering a cheap and sensitive alternative to currently available TCL scanners. 相似文献
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A method to modulate the signal of field‐effect transistor biosensors using an immunosorbent assay is described. A model system is used to show that binding of a secondary antibody, to which highly charged gold colloids are attached, to an analyte on the device floating gate can be used to induce strong electrostatic effects, which affect the device threshold voltage and source‐drain current. This process may be used for signal amplification, with the secondary binding specificity allowing for improved signal to noise ratio, which is of great importance for early disease detection. 相似文献
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This communication describes the first paper-based microfluidic device that is capable of generating its own power when a sample is added to the device. The microfluidic device contains galvanic cells (that we term "fluidic batteries") integrated directly into the microfluidic channels, which provides a direct link between a power source and an analytical function within the device. This capability is demonstrated using an example device that simultaneously powers a surface-mount UV LED and conducts an on-chip fluorescence assay. 相似文献