离子色谱的抑制及相关技术的发展

对于抑制型(双柱型)离子色谱系统,抑制系统是极为重要的一个组成部分,也是离子色谱有别于其它类型的液相色谱的最重要特点之一。抑制器的发展经历了多个发展时期,而目前商品化的离子色谱仪亦分别采用不同形式的抑制手段。近年来,还发展了一些特殊的辅助抑制器,接在抑制器的后面的CO2除去装置,都用于提高被测离子的信号或进一步降低背景电导值。     

离子色谱技术在污水监测中的应用和发展趋势

从前处理技术、色谱柱、淋洗系统、抑制器和检测项目等方面,分析总结了自20世纪80年代以来离子色谱技术在污水监测中的应用情况,并结合离子色谱技术的最新发展,分析了离子色谱技术在污水监测中的发展趋势。     

毛细管离子色谱进展

从毛细管离子色谱柱制备和毛细管离子色谱仪器研制两方面评述了毛细管离子色谱目前的发展状况.毛细管离子色谱柱包括开管离子色谱柱,毛细管颗粒填充离子色谱柱以及最近几年发展起来的整体毛细管离子色谱柱.对毛细管离子色谱仪的总结包括微流量泵、小体积进样器、适合毛细管离子色谱系统的小体积抑制器、电导和光学检测器等.     

毛细管离子色谱进展

从毛细管离子色谱柱制备和毛细管离子色谱仪器研制两方面评述了毛细管离子色谱目前的发展状况。毛细管离子色谱柱包括开管离子色谱柱，毛细管颗粒填充离子色谱柱以及最近几年发展起来的整体毛细管离子色谱柱。对毛细管离子色谱仪的总结包括微流量泵、小体积进样器、适合毛细管离子色谱系统的小体积抑制器、电导和光学检测器等。     

柱状薄层离子色谱电自生式抑制器

设计一种新型的柱状薄层离子色谱电自生式抑制器.采用多孔电极实现电极-电解液室一体化,消除了电极-电解液室的电压降;柱状薄层的抑制室结构规范了装配工艺并简化了结构,提高其抑制器的性能.     

三电极电致膜阴离子抑制器的构建

制作了一个三电极电致膜抑制器,考察了加电方式、串连电阻阻值、电极间距对改善噪声的影响。相较于传统两电极抑制器,优化得到的三电极抑制器在抑制CO_3~(2-)-淋洗液时在噪声(～2.5倍)和信噪比(2.5～3.6倍)方面皆有一定程度的改善;所得三电极抑制器稳定性好,可与离子色谱结合后检测饮料中6种常见阴离子含量。     

两性离子流动相离子色谱法测定硼酸根

1引言离子色谱已经在环境分析、质量检验、产品测定等多个领域得到了广泛的应用。离子色谱采用的抑制电导检测法测定强酸离子,会有很好的检测信号以及线性,但是对于硼酸根等弱酸离子,由于其电离常数小且电离受淋洗液pH值的影响较大,弱酸离子经过抑制器后检测信号很低。为了能够     

离子色谱电渗析技术的研究进展

电渗析器件通常定义为在电场作用下操纵离子从一种溶液穿过离子交换膜迁移到另外一种溶液的一种设备。它可以通过电解水产生氢离子或氢氧根离子,从而用于离子色谱系统的淋洗液在线制备、抑制或检测。相较于人工配制淋洗液或再生液,电渗析技术具有绿色、高效、纯度高、自动化程度高等优势。因此基于电渗析器件的离子色谱系统应用范围越来越大。该文简要评述了近几年该器件的研究进展,具体包括电致淋洗液发生器、电致膜抑制器和电渗析样品前处理器。     

XYZ-2型高性能电化学离子色谱抑制柱

本文研究离子色谱电化学抑制器的填料问题,提出以直径大小一致,中等磺化深度的球状树脂为最佳方案。改进后的抑制效率达９９．９８％,灵敏度提高了约１０％,离子的峰高及保留时间的重现性均优良（ｃ．ｖ〈２）。     

单泵柱切换离子色谱法分析复杂基体中痕量阴离子

本文通过离子色谱与柱切换技术联用实现了高浓度样品基体中的痕量阴离子检测.分别研究了不同类型基体的处理方法,使用商品化离子排斥柱和自制的聚合物色谱柱实现多种样品基体中痕量阴离子的检测.同时开发一种简化的单泵柱切换系统,利用抑制器将KOH淋洗液转化为水作为前处理柱的淋洗液,在同一个色谱系统中产生两种淋洗液,实现色谱分离与前...     

Modification of a Dionex System 12 ion chromatograph for sequential determination of the main components in atmospheric precipitation

A modification of a Dionex System 12 ion chromatograph is described which enables organic anions (acetate and formate), inorganic cations (ammonium, sodium and potassium) and inorganic anions (chloride, nitrate and sulphate) to be determined sequentially in one measuring procedure. The modified instrument consists of a programmable controller unit, a conductimetric meter, two conductimetric detectors of the Dionex System 12 ion chromatograph, the HPIC-AS4A and HPIC-CS3 modern separation units, AMMS-1 and CMMS-1 micro-membrane suppressor columns, a unique system of valves from Dionex and two dual pumps from Biotronik. The limits of detection are between about 1 and 3 micrograms/l for chloride, nitrate and sulphate and between about 2 and 10 micrograms/l for acetate, formate, ammonium, sodium and potassium. The reliability of the method was demonstrated by analysing two NBS simulated rain water Standard Reference Materials. Some examples are given of the application of the method to the sequential determination of the main precipitation components in typical samples from urban and rural regions of the F.R.G. The ion concentrations varied between about 0.02 and 300 mg/l.     

DX-2000I型离子色谱仪的改进

介绍DX－2000I型离子色谱仪改进的要点。改进后，该仪器具有DX－300型离子色谱仪的功能，能满足大亚湾核电站生产控制的需要。     

Two-dimensional high resolution GLC environmental analysis,preliminary results

Summary The current status of gas chromatographic procedures and instrumentation for the analysis of volatile environmental contaminants is discussed. Design features of gas chromatographic systems, capable of transferring portions of eluting compounds from one gas chromatographic column into another are also discussed. A prototype two-dimensional gas chromatograph has been built and tested. The system is composed of two separate gas chroamtographs, which are joined by a common heated interface. A combination of off-line valves and restrictors (Deans' switches) serves to change carrier gas flow directions. Compounds selected for cutting are transferred to the second gas chromatograph and held in an intermediate trap. The effluents from the second column are detected by FID/ECD, operated in parallel. Important parameters which effect sample transfer between the systems have been studied to serve as basis for a semiautomated instrument to be built. Some applications with synthetic mixtures are demonstrated.     

Resistively heated temperature programmable silicon micromachined gas chromatography with differential mobility spectrometry

A microfabricated electromechanical system based on radio frequency modulated ion mobility spectrometry (MEMS-RFIMS), also known as differential ion mobility spectrometry (DMS) has been successfully interfaced to a custom-fabricated resistively heated temperature programmable micromachined gas chromatograph. In contrast to a conventional time-of-flight ion mobility spectrometer, the DMS uses the non-linear mobility dependence in strong radio frequency electric fields for ion filtering. Selective and sensitive detection of targeted analytes of interest can be achieved by using different transport gases, radio frequencies, and associated compensation voltages. In addition, the detection of both positive and negative ions, depending on the ionization mechanism favorable to the analytes involved is achieved. When compared to a stand-alone GC with a non spectrometric detector or a stand-alone DMS, GC-DMS as a hyphenated technique offers two competitive advantages; two orthogonal separating methods in a single analytical system and the resolving power of gas chromatography to minimize charge exchange in the ionization chamber of the detector. In this article, a portable, resistively heated temperature programmable silicon machined gas chromatograph with differential mobility detection is introduced. The performance of the instrument is illustrated with examples of difficult industrial applications.     

A portable gas chromatograph with air carrier gas for the determination of explosive traces

A three-step scheme for a miniature air purification filter for a gas chromatograph has been proposed. A method for controlling the selectivity of a new ion gas chromatography detector has been considered using a simulating model. The possibility of determining explosive traces by a gas chromatograph with air as a carrier gas has been demonstrated.     

Ion chromatographic system with a novel switching suppression device

Ion chromatography (IC) has been a powerful tool for measuring ionic species in environmental samples such as tap, river and drain waters. Suppressor modules (membrane and disposable column types) have been used for reducing the background of a baseline. A new type of suppressor device, which has a suppressor resin and switching valve was developed. Fresh ionic resin is introduced into a groove for each analysis to perform the suppression of the working eluent. The eluent composition for obtaining higher sensitivity and better resolutions among ionic species and carbonate ion was also investigated. Although carbonate buffers are used for ion separation in general, the separation of carbonate ion from other ions was not achieved. A borate eluent resulted in good resolutions and higher sensitivity. A new column was also developed for obtaining higher column efficiency and resolution. The optimization of anion separation using a new IC system (IC-2001) that consists of a new suppressor device, an anion-exchange column (TSKgel SuperIC-Anion, 150x4.6 mm), an autosampler, a conductivity cell and a pump in a compact module is described.     

Finnigan MAT95高分辨率气相色谱质谱联用仪离子源恒温控制系统故障的分析与排除

介绍了德国Ｆｉｎｎｉｇａｎ公司生产的ＭＡＴ９５型气相和液相色谱（ＧＣ／ＭＳ）联用仪离子源加热系统故障的分析、检查和排除的方法。类似仪器故障的分析与排除具有较好的参考价值。     

On-line recording of 13C/12C ratios and mass spectra in one gas chromatographic analysis

An isotope ratio mass spectrometer and an ion trap mass spectrometer have been coupled in parallel to one gas chromatograph. Using this arrangement both the ¹³C/¹²C ratio and the mass spectrum of a given compound can be measured simultaneously under identical gas chromatographic conditions. Although column connection fittings are employed to split the capillary eluate, chromatographic performance was barely impaired. Development of the system has been monitored by recording δ¹³C values of the constituents of Grob test mixture no. 2. The accuracy and reliability of system performance has also been tested.     

Operation of an Improved,Continuous Annular Chromatograph

Abstract

A rotating annular chromatograph has been demonstrated to have utility in the continuous separation of solutes in a feed stream. Recent modifications to the system have resulted in a more efficient separation. Design of the inlet and the exit has been significantly changed to improve chromatograph performance. Refinements have also been made to the method of gradient elution. The effects of changing superficial velocity and initial resin loading on the height equivalent to a theoretical plate are shown for the ternary nickel-cobalt carbonate amine system. A continuous separation of this ternary mixture utilizing pH gradient elution is presented.     

Development and optimization of organic acid analysis in tobacco with ion chromatography and suppressed conductivity detection

With the aid of a central composite face-centered design, an ion chromatographic method was developed and optimized for analyzing organic acids in tobacco. A Dionex-100 ion chromatograph with an ion suppressor and a conductivity detector, and a Bio-Rad Aminex HPX-87H column were employed. Only 13 analyses were required to optimize two factors: column temperature and eluent strength. Two sets of optimal conditions for separating nine acids were found: 1.8 mM HFBA eluent and 42 °C column temperature, and 0.8 mM HFBA eluent and 50 °C column temperature. The flow-rate was 0.6 ml min⁻¹ and the analysis time was 18 min or less. A sample preparation procedure included extraction of 2 g ground tobacco with 100 ml of 5 mM sulfuric acid solution for 3 h, filtration of the extract, and dilution of the filtrate 10-fold with deionized water.