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1.
溶剂浮选是一种被气泡传质效应强化的液-液萃取技术,具有高分离效率、高富集系数、传质温和、低有机溶剂消耗、操作简单等优点,广泛应用于仪器分析的样品前处理、水体中有机污染物的分离富集、天然产物中活性物质分离等领域。本文比较全面地综述了溶剂浮选技术的通用模式、分离参数、应用现状和理论研究进展;在此基础上,重点介绍了近些年溶剂浮选领域出现的一些新分离模式和应用领域:新的分离模式主要是"双水相浮选"和"气浮络合萃取",新的应用领域主要是样品前处理技术的新应用以及对天然产物提取液中活性物质的分离富集。  相似文献   

2.
绿色分析化学技术研究进展   总被引:1,自引:0,他引:1  
绿色分析化学是受到广泛关注的一门前沿科学,它是把绿色化学的基本原理应用在新的分析方法和技术方面.对绿色分析样品前处理技术、绿色分析分离富集技术和绿色分析测试技术进行了综述.  相似文献   

3.
刘玉兰  陈雅莉  肖小华  夏凌  李攻科 《色谱》2020,38(10):1197-1205
样品前处理能将待测物从复杂基质中预先分离富集出来,以提高分析方法的灵敏度、选择性和准确性,是复杂样品分析的关键步骤。样品前处理是一个非自发的、从无序到有序的熵减过程,不仅费时费力,还极易引起误差。向体系输入能量和降低体系熵值可以增强分离富集效果,加快样品制备过程。将电场引入在线样品前处理,既能向体系做功,又能驱动样品定向迁移,使前处理的熵减过程快速顺利进行,是快速样品制备的有效途径。基于电驱动的在线分离富集技术综合了多种加速策略:(1)以电场形式向体系输入能量,加速传质和传热过程;(2)采用电渗流、电泳等电驱动定向流实现样品在分离、富集、检测各步骤之间的定向迁移,保证样品前处理与检测顺利进行;(3)利用在线联用技术集成样品前处理与分析检测各步骤,从而提高自动化程度,减少人为误差;(4)通过微型化装置或微萃取方法提高样品制备效率,缩短样品制备时间。该文总结了近10年与基于电驱动的在线快速分离富集技术相关的90多篇文献,综述了该技术领域的研究进展,探讨了电驱动毛细管在线快速分离富集技术、电驱动芯片在线快速分离富集技术和电驱动膜萃取在线分离富集技术各自的优势和潜力,并展望了该类技术的发展与应用趋势。  相似文献   

4.
贵金属元素分离富集技术进展   总被引:1,自引:0,他引:1       下载免费PDF全文
本文介绍了近10年来国内外贵金属分析中的分离富集技术进展情况。并分别对火试金分离法、共沉淀法、溶剂萃取法、离子交换法、萃淋树脂法、液膜分离法、吸附剂法等多种分离富集技术进行了评述。最后对未来贵金属元素分离富集技术发展趋势进行了展望  相似文献   

5.
活性炭分离富集技术的应用新进展   总被引:5,自引:0,他引:5  
对活性炭分离富集技术的应用新进展进行综述。重点评述了活性炭的结构和吸附机理,活性炭对有机物的分离和吸附,活性炭对金属离子的分离和富集,共引用文献35篇。  相似文献   

6.
夏立钧  陶凤群  胡振元 《色谱》1988,6(2):73-76
 〕本文对在线富集—高效液相色谱分析法中影响色谱分离的一些因素进行了探讨。实验表明,采用填装较小粒度富集剂的短柱及减小富集物的洗脱体积能使色谱分离获得改善。富集柱与HPLC柱间的匹配对色谱分离起着重要作用。方法适宜于分离具有较大k'值的水中痕哿坑有机物。  相似文献   

7.
贾荫楠  田华  贺军辉  冯利利 《化学通报》2019,82(10):878-885
污染物富集分离是环境样品前处理过程中的关键环节,对污染物分析监测的准确性和灵敏性至关重要。目前,有效的富集分离仍然是环境分析的瓶颈问题。本文以水中典型的有机污染物六六六和无机污染物汞为对象,结合近期最新的研究报道,概述了水体环境中六六六和汞富集分离的研究新进展,就环境纳米材料在富集分离过程中的应用提出了存在的问题,并对其发展前景进行了展望。  相似文献   

8.
铊的分离富集技术   总被引:7,自引:1,他引:6  
对近二十年来重金属铊的重要的和最新的分离富集技术作了系统总结和评述,并提出了在不同情况下铊分离富集方法的最优化选择,对其未来发展趋势进行了展望。  相似文献   

9.
原子吸收光谱法已成为测定金的主要方法。但对样品要进行分离富集处理,金的分离与富集方法很多。我们在文献的基础上,利用磷酸兰丁酯(TBP)一盐酸体系,以聚四氟乙烯作载体的萃取色层法来分离富集微量金。并对洗脱剂的选择进行了探讨,选用硫脲(TU)-盐酸洗脱  相似文献   

10.
蛋白质糖基化在调节各种复杂的生物过程中,如分子识别、免疫应答和蛋白质折叠等起着至关重要的作用。由于糖肽/糖蛋白在复杂生物样品或临床样品中丰度较低,进行糖蛋白组学分析前往往需要进行目标蛋白的分离富集。研究开发具有高效糖蛋白分离富集能力的新型材料对糖蛋白/糖肽的研究具有重要意义。近年来报道了许多新型糖蛋白分离富集材料,如有机高分子材料、生物基材料、新型有机骨架材料和新型功能复合材料等。这些材料因其结构、生物相容性和理化性质等特点,从不同层面推动了糖蛋白分离富集技术的发展。本文就目前国内外有关糖肽/糖蛋白分离富集的新型材料进行了总结和讨论,并对其未来发展提出展望。  相似文献   

11.
Abstract

Instrumental and manual methods currently available for the measurement of atmospheric oxidants are surveyed. Techniques used in the United States are emphasized and their advantages and disadvantages are discussed. Commercial systems are evaluated in terms of general operating principles rather than of specific instruments. The ability of these techniques to meet the measurement requirements defined by U.S. Federal air quality oxidant criteria are discussed. Alternative chemical techniques that may have some advantages over the neutral, buffered KI procedure are discussed. Also some attractive, alternative instrumental procedures that are ozone-specific are presented. These systems are based on chemiluminescence and ultraviolet absorption photometry. Electrochemical and colorimetric methods for total oxidant measurements are compared. Finally, some data are presented on relationships of ozone and total oxidants.  相似文献   

12.
Measurements of densities, speeds of sound, excess volumes and viscosities of binary mixture of methyl tert-butyl ether with tetralin and decalin are reported at 303.15?K over the entire range of composition. Excess volumes are measured using batch dilatometer technique. Sound speeds are obtained using ultrasonic interferometer. Densities are computed from excess volume data. Isentropic compressibilities are derived from density and sound speed data. Speeds of sound are evaluated on the basis of Jacobson's free length theory and Schaff's collision factor theory. The predicted values are in good agreement with the experimental results. The viscosity data are analysed on the basis of corresponding states approach. Excess volumes and deviation in isentropic compressibilities are negative and deviation in viscosities are positive over the entire composition range. The experimental results are discussed in terms of possible molecular interactions between unlike molecules.  相似文献   

13.
14.
若干含多硫基的配合物的合成方法及结构特征   总被引:1,自引:0,他引:1  
本文综述了近年来我们合成的十二种多硫基的配合物,这些配合物含有S^2-2,S^2-4,S^2-5,S^2-6,S^2-7等多硫革配体,总结了这些配合物中的金属配位构型,比较了各种多硫基的S-S键长及有关键角,归纳了配合物外光谱,并阐述了其中几个配合物与NH2NH2的反应性能。  相似文献   

15.
Pumera M 《Talanta》2007,74(3):358-364
Different methods for construction of contactless conductivity detectors (CCD) for microchip electrophoresis device are described in this review. This includes three main schemes of CCD for microchips, such as (i) the detection electrodes are placed along the microchannel from outside of the microchip and they are insulated from the channel by the cover lid of microchip device; (ii) the electrodes are placed across of the microchannel in the same plane and they are insulated by thin separation channel walls and (iii) electrodes are buried in widened part of microchannel and they are insulated from solution by ultrathin layer of silicon carbide. Specific issues related to the CCD on microfluidics are discussed, such as an influence of shape and magnitude of ac voltage and placement of electrodes and their insulation. Various applications for security, pharmacological, bioassays and food analysis purposes are described.  相似文献   

16.
钼、钨系过氧化物是非常重要的Sharpless烯烃环氧化催化剂,有着非常广泛的工业发展前景。本文综述了钼、钨系过氧化物的种类,结构,合成方法及催化活性,分析了各种钼、钨系过氧化物的特点以及在催化环氧化领域的发展现状。同时,本文还讨论了钼、钨系过氧化物催化烯烃环氧化反应的机理。评述了在催化环氧化领域中两种主要理论——Mimoun机理与Sharpless机理的争论焦点及发展现状,以及计算化学对两种理论中间过渡态的研究进展,并且重点分析了Sharpless机理的过渡态结构。此外,本文还综述了影响钼、钨系过氧化物催化剂反应活性的各种因素以及质子所产生的副反应。最后,本文对应用于催化环氧化领域的钼、钨系过氧化物未来的研究方向提出了建议。  相似文献   

17.
Spices and herbs are among the most commonly adulterated food types. This is because spices are widely used to process food. Spices not only enhance the flavor and taste of food, but they are also sources of numerous bioactive compounds that are significantly beneficial for health. The healing effects of spices are connected with their antimicrobial, anti-inflammatory and carminative properties. However, regular consumption of adulterated spices may cause fatal damage to our system because adulterants in most cases are unhealthy. For that reason, the appropriate analytical methods are necessary for quality assurance and to ensure the authenticity of spices. Spectroscopic methods are gaining interest as they are fast, require little or no sample preparation, and provide rich structural information. This review provides an overview of the application of NMR spectroscopy combined with chemometric analysis to determine the quality and adulteration of spices.  相似文献   

18.
Ng Seik Weng 《结构化学》2005,24(12):1425-1439
1 INTRODUCTION finement stage. The person performing the crysta- llographic manipulations works on numerical data The high degree of order in the arrangement of that are quite different from the diffraction images atoms in a crystal is a fundamental characteristic of on a computer terminal, and most often does not even the crystalline state, an ideal crystal being envisaged see the images. to be constructed of regularly-stacked unit cells, each The refinement program, SHELXL-97[1], has …  相似文献   

19.
Peculiarities of [8+2] cycloaddition of acetylenes to indolizines are reviewed. Especially mentioned are indolizines with leaving groups at positions 3 and 5. Cycloaddition to aza- and benzo derivatives are reviewed, as well as 1,10-cyclizations and processes leading to cyclazines where indolizines are intermediates. Mechanistic features (adducts and cycloadducts) and theoretical aspects (one- or two-steps mechanism) are reviewed.  相似文献   

20.
The alternate multiple adsorption layers of macrocations and macroanions on the surfaces of colloidal spheres, in which the complexation mixtures are deionized with ion-exchange resins are studied with help of the electrophoretic light-scattering, dynamic light-scattering and transmitted electron-microscopy techniques. The results are compared with those without resins. Colloidal silica spheres (110 nm in diameter) and monodispersed polystyrene spheres (220 nm) are used as colloidal spheres. The macrocations used are poly (4-vinyl-N-n-butyl pyridinium bromide) and poly (allylamine hydrochloride). Sodium poly (styrene sulfonate) and sodium polyacrylate are used as macroanions. The macroion-colloid complexations are formed firmly when the complexation suspensions are deionized with the resins.  相似文献   

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