共查询到20条相似文献,搜索用时 78 毫秒
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《色谱》2016,(2)
光学吸收检测器是液相色谱仪最常用的检测器之一,检测池是此种检测器的核心部分,是获得光穿过样品信息的重要部件,其设计影响检测器的性能。为了提高检测器的信噪比,减小检测池引起的色谱峰展宽,需要设计更长光程、更小体积的检测池,同时还要保证一定的光通量。受加工技术的限制,增大光程、减小池体积和保证光通量通常很难兼顾,这对优化检测池的设计和加工、提高检测器性能提出了挑战。本文以光学吸收检测器的检测原理为基础,从增大光程、减小体积、利用全反射等角度综述了检测池设计的研究进展,同时对部分检测池的设计进行了详细说明。这些不同的设计思路和结构对于检测池的设计以及光学吸收检测器的研发具有指导意义。 相似文献
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阐述了高效毛细管电泳电化学检测器(包括电导、电势和安培检测)的研究现状,重点是检测器的研制及接口的制作技术。对各种电化学检测器的应用情况也进行了总结。展望了高效毛细管电泳电化学检测的发展前景。 相似文献
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高效液相色谱法适用的范围很广,是非常重要的分析方法之一,它在医药学及生命科学中已成为一种主要的分离检测手段。与分离方法迅速发展的同时,检测技术的不断进步也是高效液相色谱技术得到广泛应用的原因之一。近年来高效液相色谱检测技术从最常用的紫外可见分光光度检测器和差示折光检测器开始,已经发展了诸如能够实时定性和定量的二极管阵列紫外可见分光光度检测器,能够快速扫描和光谱分辨率更高的色散型紫外可见分光光度检测器以及适用于生物化学的电化学检测器等等。各种联用检测手段如与质谱联用的热喷雾和粒子束接口等已日趋成熟,与傅里叶变换红外光谱和拉曼光谱的联用技术亦在发展中。各种检测器的灵敏度、线性范围、稳定性和重现性等主要指标日益提高。许多新的检测手段已为科技工作者所熟悉和使用。目前比较引人注目和发展较快的为手性化合物 相似文献
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高效毛细管电泳—电荷耦合器件检测器联用技术研究:Ⅵ.激光诱导… 总被引:4,自引:0,他引:4
本文报道利用电荷耦合器件检测器、氩离子激光器等设备,组装成的激光诱导多波长荧光检测毛细管电泳装置。并与普通钨灯光源组成的装置进行比较,表明激光诱导荧光检测装置具有更高的灵敏度、分辨率和分离效率。 相似文献
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The optical characteristics of on-capillary photometric detectors for capillary electrophoresis were evaluated and five commercial detectors were compared. Plots of sensitivity (absorbance/concentration) versus absorbance obtained with a suitable testing solution yield both the linear range and the effective path length of the detector. The detector linearity is a crucial parameter when using absorbing electrolytes, such as for indirect photometric detection, and especially for highly absorbing electrolyte probe ions. The upper limits of the linear ranges (determined as 5% decline in sensitivity) for five commercial detectors ranged from 0.175 to 1.2 AU. The effective pathlength reflects the quality of the optical design of the detector and is equal to the capillary internal diameter only for a light beam passing exactly through the capillary centre, but becomes progressively shorter for imperfect optical designs. The determined effective pathlength for the five investigated detectors ranged from 49.7 to 64.6 microm for a 75 microm I.D. capillary. 相似文献
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《Radiation Physics and Chemistry》2008,77(9):1002-1004
In the present work, we have determined the bulk-etch rates of a newly developed track detector called poly-[N-allyloxycarbonyl diethanolamine-bis allylcarbonate] (PNADAC) homopolymer at different temperatures to deduce its activation energy. The energy of activation is found to be (1.02±0.04) eV. This compares very well with the values of activation energy reported in the literature for the most commonly used nuclear track detectors. The effects of gamma irradiation on this new detector in the dose range of 4.7–14.5 Mrad have also been studied using UV–visible spectroscopic technique. The optical band gaps of the unirradiated and the gamma-irradiated detectors determined from the UV–visible spectra were found to decrease with the increase in gamma dose. These results have been explained on the basis of scission of the detector due to gamma irradiation. 相似文献
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In separations in capillaries or on chips, the most predominant detectors outside of the field of proteomics are electrochemical (EC) and optical. These detectors operate in the μM to pM range on nL peak volumes with ms time resolution. The driving forces for improvement are different for the two classes of detectors.With EC detectors, there are two limitations that the field is trying to overcome. One is the ever-present surface of the electrode which, while often advantageous for its catalytic or adsorptive properties, is also frequently responsible for changes in sensitivity over time. The other is the decoupling of the electrical systems that operate electrokinetic separations from the system operating the detector.With optical detectors, there are similarly a small number of important limitations. One is the need to bring the portability (size, weight and power requirements) of the detection system into the range of EC detectors. The other is broadening and simplifying the applications of fluorescence detection, as it almost always involves derivatization.Limitations aside, the ability to make detector electrodes and focused laser beams of the order of 1 μm in size, and the rapid time response of both detectors has vaulted capillary and chip separations to the forefront of small sample, fast, low mass-detection limit analysis. 相似文献
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Colin W. Earle Mark E. Baker M.Bonner Denton Robert S. Pomeroy 《Trends in analytical chemistry : TRAC》1993,12(10):395-403
Scientific charge transfer devices (CTDs) are rapidly becoming the detector of choice for optical chemical analysis. The high sensitivity and resolution of these detectors make them ideal for a wide range of chemical imaging applications. In this article we highlight some of the current trends and future research directions of CTDs as imaging detectors for chemical analysis. 相似文献
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Duc T. Vo 《Journal of Radioanalytical and Nuclear Chemistry》2008,276(3):693-698
Uranium enrichment and holdup measurements require a detector capable of accurately obtaining the 186-keV peak area. NaI detectors
have been widely used for these tasks. However, for recycled uranium, the interference of the 239-keV peak from the 232U decay chain challenges the capabilities of the NaI detectors to accurately extract the area of the 186-keV peak. Using CZT
detectors, which have much better resolution than the NaI detectors, has temporarily solved this interference problem. However,
the CZT detectors have setbacks in that they are generally small and have low efficiencies, which require long acquisition
times for reasonable statistics. Recently, two new types of scintillator detectors have become available commercially, LaCl3(Ce) and LaBr3(Ce). These cerium-doped lanthanum halide detectors, with comparable resolution but better efficiency than the CZT detectors,
appear to permanently solve the interference problem for recycled uranium measurements. In this report, we compare the uranium
enrichment measurement performances of a portable NaI detector, a large coplanar-grid CZT detector, and a LaBr3 detector. 相似文献
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Flow optimization, optical discrimination, and doping with carbon disulfide or methane were tested as means of distinguishing selenium peaks from sulfur peaks in a flame photometric detector. Optical discrimination is the best choice if a dual-channel detector is available. For single-channel detectors, methane doping quenches the sulfur peak more severely than the selenium peak, thus allowing the peaks to be identified. 相似文献
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M. Mirhabibi A. Negarestani M. A. Bolorizadeh M. R. Rezaei A. Akhound 《Journal of Radioanalytical and Nuclear Chemistry》2014,301(1):207-211
Temporal variations of radon concentration in soil before the earthquake are known as an earthquake precursor. For using of radon as an earthquake precursor, it is necessary to constantly monitor radon concentration variations in a relatively wide range in the vicinity of a fault which is virtually impossible for radon detectors that already exist. This paper proposes a new method for continuous measurement of radon concentration variations in a wide range, using optical fiber as radon detector. For this purpose, an experimental system consisting of radon source, optical-fiber holding chamber, radon gas detector, optical laser source, and optical power meter have been arranged to with the aim to create different concentrations of radon gas in the vicinity of the optical fiber; the attenuation which creates on optical fiber is subsequently measured. As a result, the average of the attenuation is 0.004 μw per each meter per Bq/l since the fault’s length is more than ten kilometers; sensitivity of the measurement can be improved many times over. 相似文献
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Flow-through spectroelectrochemical detectors for flow-injection systems and liquid chromatography are described. The detectors have a rectangular flow channel with a reticulated vitreous carbon working electrode followed by an open optical window. The dead volumes of the cells are 27 μl (liquid chromatography) and 80 μl (flow injection). In situ spectral monitoring of reaction products and intermediates for compounds that are both weakly and highly absorbing is demonstrated by using o-tolidine and N,N,N′,N′-tetramethyl-p-phenylenediamine. As a detector for flow-injection systems, components in two-component mixtures can be quantified. As a detector for liquid chromatography, simultaneous absorbance and electrochemical chromatograms allow more eluting compounds to be identified and quantified. Mixtures of nitro- and chloro-phenols are used to illustrate the simultaneous profiling of spectral and redox properties. 相似文献
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Amol Mhatre P. C. Kalsi Onkar Singh Choudhary G. P. Sachdev 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(3):795-798
The gamma irradiation effects in the dose range of 2.5?C43.0 Mrad on the etching and optical characteristics of CR-39 solid state nuclear track detector (SSNTD) have been studied by using etching and UV?CVisible spectroscopic techniques. From the measured bulk etch rates at different temperatures, the activation energies for bulk etching at different doses have also been determined. It is seen that the bulk etch rates increase and the activation energies for bulk etching decrease with the increase in gamma dose. The optical band gaps of the unirradiated and the gamma -irradiated detectors determined from the UV?CVisible spectra were found to decrease with the increase in gamma dose. These results have been explained on the basis of scission of the detector due to gamma irradiation. The present studies can be used for the estimation of gamma dose in the range of 2.5?C43.0 Mrad and can also be used for estimating track registration efficiency in the presence of gamma dose. The CR-39 detector has also been applied for the assay of uranium in some soil samples of Jammu city. 相似文献