拉曼光谱技术在高分子表征研究中的应用

拉曼光谱作为一种强大的工具,被广泛应用于聚合物结构的表征.随着共振拉曼光谱、扫描角度拉曼光谱、高分辨率拉曼成像、极化拉曼光谱、表面增强拉曼散射等拉曼技术的迅速发展,拉曼光谱的应用范围不断扩大.本文首先介绍了拉曼光谱设备的基本原理和组成,总结了拉曼技术的实验技巧和数据处理中需要注意的问题,讨论了红外光谱和拉曼光谱的区别,在此基础上,综述了近十年来拉曼技术在聚合物结构表征领域的最新应用和研究进展.其应用包括以下六个方面:高分子链的构象、聚合物的聚集状态、聚合物结晶度的计算、高分子链的取向、外场作用下的结构转化、高分子共混物化学或物理成分的识别.最后,对拉曼光谱在聚合物研究中的发展进行了展望.希望本文能够对试图从拉曼光谱中获取聚合物结构信息的学者有所帮助.     

紫外拉曼光谱：破解催化剂技术瓶颈

新材料作为高新技术的基础和先导,应用范围广泛,是21世纪最重要和最具有发展潜力的领域,而新材料的研制与催化剂的使用是分不开的。大连化物所凝聚科学技术研究团队的催化材料紫外拉曼光谱技术,破解了催化材料的若干关键技术难题。该成果获得了2011年度国家自然科学二等奖。紫外拉曼光谱技术破解了世界催化材料发展瓶颈,解决了催化材料关键科学难题,实现了4大突破。     

拉曼积分球对水中微量硫酸根和碳酸氢根离子定量分析可行性研究

拉曼光谱因非接触、无损、指纹光谱特性,广泛应用于科学研究领域,主要集中于定性研究,拉曼光谱定量分析较为缺乏,尤其在液体中的定量分析研究明显不足.因此,有必要进一步开展水中拉曼光谱定量分析研究.探讨了将拉曼积分球应用于液体拉曼光谱定量分析技术,对水中SO24-和HCO-3进行了定量分析可行性研究.定量分析基于内标法,选取...     

表面增强拉曼光谱:应用和发展

表面增强拉曼光谱技术(Surface-enhanced Raman spectroscopy,SERS)是一种具有超高灵敏度的指纹光谱技术,目前已广泛应用于表面科学、材料科学、生物医学、药物分析、食品安全、环境检测等领域,是一种极具潜力的痕量分析技术。 本文对SERS技术及相关的针尖增强拉曼光谱(Tip-enhanced Raman spectroscopy,TERS),壳层隔绝纳米粒子增强拉曼光谱(Shell-isolated nanoparticle-enhanced Raman spectroscopy,SHINERS)技术的发展及应用进行了综合评述,并探讨了其未来的研究热点及发展方向。     

拉曼光谱技术在现场快检分析领域中的应用

拉曼光谱技术以其操作简单、无损、快速、需样量少和适合含水体系分析等独特优势,加之表面增强拉曼散射技术的高灵敏特性,现已广泛应用于现场快检分析领域。该文从直接检测和间接检测两个方面,通过分析食品安全、刑事侦查、医药管理、环境监测等领域的典型示例,对拉曼光谱技术在现场快检领域中的应用及其研究进展进行了归纳总结,并展望了其在现场快检领域中的发展趋势。     

拉曼光谱技术在聚合物研究中的应用进展

拉曼光谱可以提供分子的振动信息,对于聚合物分子链的构象和链间的相互作用非常敏感,能够提供聚合物固体、薄膜或溶液的物理化学特性信息,如聚合物的结构单元、空间构型、晶态结构、分子链的物理构象或分子链子链和侧基在界面间或在各向异性材料中的排列等链取向信息等。因此拉曼光谱作为一种原位无损检测技术,其衍生出的表面增强拉曼光谱技术(Surface-enhanced Raman Scattering,SERS)、变温拉曼光谱技术、共焦显微拉曼光谱技术(Confocal Raman Microscopy,CRM)、拉曼Mapping成像技术和共振拉曼散射技术(Resonance Raman scattering,RRS)等,广泛应用于物理、化学和生物医学等领域。本文从拉曼光谱的基本理论基础、拉曼光谱技术及其在聚合物研究中的最新应用进展等方面进行综述,以探索扩展拉曼光谱技术在高分子物理与化学领域中许多问题,如分子链的构象结构、分子链的结晶行为、分子链的扩散运动和共混体系相态结构变化等方面的应用。     

拉曼光谱技术在色谱分析检测中的应用

讨论了色谱分离与拉曼光谱检测的联用技术。表面增强拉曼光谱技术和紫外共振拉曼光谱技术克服了常规拉曼光谱技术所固有的灵敏度低的问题,所设计的与液相色谱联用的装置可以获取色谱柱流出液的拉曼光谱。评价了联用装置的重现性、动态范围和分析潜力,发现表面增强拉曼光谱仪和紫外共振拉曼光谱仪都可以作为薄层色谱、液相色谱法的检测器,可提供待测组分的结构信息,其灵敏度和其它常用检测器相似。     

拉曼光谱技术及其应用进展

拉曼光谱作为一种无损分析方法,可以快速、精准地得到包括固体、粉末、液体、气体、胶体等不同类型样品的化学结构、相和形态、结晶度以及分子间相互作用等相关信息,因此被广泛应用于诸多领域。本文介绍了拉曼光谱的基本工作原理;总结了近年来拉曼光谱在环境检测、材料、食品安全、医疗、刑侦司法、勘探、工业等领域的应用,以期为今后拉曼光谱检测领域更好地发展提供参考。     

现场光谱电化学研究的新进展

电化学以两个凝聚相的荷电界面为其主要研究对象．它广泛地应用于能源、材料等重要科学领域，并对生命科学的发展发挥着重要作用［1，2］．为了从分子水平上深化对电化学界面的认识，自七十年代中至八十年代初采用了紫外可见反射、拉曼和红外光谱技术对电化学体系进行现场（in-situ，又称原位）研究，开创了光谱电化学新领域[3,4]．光谱电化学在／＼十年代发展迅速，推动电化学研究由宏观进入微观、由统计平均深入至分子水平【‘一刀．近年来，随着各种光谱仪器性能的提高以及非线性光谱等新技术的发展，现场光谱电化学研究不断拓宽新领域，…     

基于表面增强拉曼光谱微流控芯片的研究进展

微流控芯片实验室是一种以在微米尺度的空间中对流体进行操控为主要特征的技术,具有灵活集成多种单元技术,降低样品消耗量等优势。拉曼光谱是一项重要的现代光谱技术,被广泛应用于化学、物理和生物科学等诸多学科领域,基于纳米银或金粒子的表面增强拉曼(SERS)技术具有非常高的灵敏度,可对环境中的污染物和生物分析样品进行痕量分析。该文主要对表面增强拉曼光谱微流控芯片领域的研究进展进行总结,包括纳米粒子合成、芯片设计以及常见的传感器类型,介绍了其在生命科学、环境监测等领域的应用,显示了其广阔的应用前景。     

国内光催化研究进展简述

分1975~1985, 1985~1995和1995~2012三个时期简要介绍了国内光催化研究进展, 主要侧重于光催化材料及其改性、应用和反应机理方面的研究进展, 并指出了当前光催化领域存在的一些重要问题和未来的发展趋势, 涉及到光解水、CO₂还原、环境净化和选择性有机合成等方面.     

青蒿素研究进展

青蒿素是目前治疗疟疾的特效药。本文对自青蒿素发现以来的最新研究进展进行了比较详尽的综述。内容包括: 青蒿素的发现及历史, 青蒿素的来源, 青蒿素的全合成,青蒿素的生物合成, 青蒿素衍生物以及植物组织培养生产青蒿素。     

Recent Advances in Analytical Methodology for in vivo Electrochemistry in Mammals

Electrochemistry is one of the most advanced techniques for monitoring neurochemical activities in the living brain because electrochemical approaches bear the advantageous features of high spatial and temporal resolutions, which facilitate its tremendous potential in investigating the highly spatially heterogeneous brain system and the fast dynamics of neurochemical activities. On the other hand, since brain is the most complicated organ in the sense of its numerous kinds of neurochemical species, high selectivity is always required for any analytical methods that approach the brain. In this review, we will discuss various electrochemical methodologies to achieve selective detection of neurochemicals in mammalian brain and the strategies developed mainly by our group towards selective monitoring of both electrochemically active and inactive neurochemicals. At the end, we will discuss possible solutions towards brain mapping of neurochemical species and combination of neurochemical detection strategy with electrophysiology as the direction of future development of electroanalysis in living brain.     

Interpretation of inorganic arsenic metabolism in humans in the light of observations made in vitro and in vivo in the rat

The toxicity of inorganic trivalent arsenic for living organisms is reduced by in vivo methylation of the element. In man, this biotransformation leads to the synthesis of monomethylarsonic (MMA) and dimethylarsinic (DMA) acids, which are efficiently eliminated in urine along with the unchanged form (As_i). In order to document the methylation process in humans, the kinetics of As_i, MMA and DMA elimination were studied in volunteers given a single dose of one of these three arsenicals or repeated doses of As_i. The arsenic methylation efficiency was also assessed in subjects acutely intoxicated with arsenic trioxide (As₂O₃) and in patients with liver diseases. Several observations in humans can be explained by the properties of the enzymic systems involved in the methylation process which we have characterized in vitro and in vivo in rats as follows: (1) production of As_i metabolites is catalyzed by an enzymic system whose activity is highest in liver cytosol; (2) different enzymic activities, using the same methyl group donor (S-adenosylmethionine), lead to the production of mono- and di-methylated derivatives which are excreted in urine as MMA and DMA; (3) dimethylating activity is highly sensitive to inhibition by excess of inorganic arsenic; (4) reduced glutathione concentration in liver moderates the arsenic methylation process through several mechanisms, e.g. stimulation of the first methylation reaction leading to MMA, facilitation of As_i uptake by hepatocytes, stimulation of the biliary excretion of the element, reduction of pentavalent forms before methylation, and protection of a reducing environment in the cells necessary to maintain the activity of the enzymic systems.     

Use of NAA in marine environment and in archaeology in Greece

Neutron activation analysis (NAA) is a very sensitive and accurate multielement analytical method that is widely applied to the investigation of environmental and archaeological problems. The first part of this paper is a review of pollution studies of toxic trace elements in sediments, seawater and marine organisms of Saronikos Gulf, Greece by NAA. The second part of this paper is a review of provenance studies based on minor and trace element research in ancient ceramics, obsidian, flint, limestone, marble and lead by Instrumental NAA, performed at the NCSR Demokritos.     

Electrolysis in nanochannels for in situ reagent generation in confined geometries

In situ generation of reactive species within confined geometries, such as nanopores or nanochannels is of significant interest in overcoming mass transport limitations in chemical reactivity. Solvent electrolysis is a simple process that can readily be coupled to nanochannels for the electrochemical generation of reactive species, such as H(2). Here the production of hydrogen-rich liquid volumes within nanofluidic structures, without bubble nucleation or nanochannel occlusion, is explored both experimentally and by modeling. Devices comprised of multiple horizontal nanochannels intersecting planar working and quasi-reference electrodes were constructed and used to study the effects of confinement and reduced working volume on the electrochemical reduction of H(2)O to H(2) and OH(-). H(2) production in the nanochannel-embedded electrode reactor output was monitored by fluorescence emission of fluorescein, which exhibits a pH-dependent emission intensity. Initially, the fluorescein solution was buffered to pH 6.0 prior to stepping the potential cathodic of E(0)' for the generation of OH(-) and H(2). Because the electrochemical products are obtained in a 2:1 stoichiometry, local measurements of pH during and after the cathodic potential steps can be converted into H(2) production rates. Independent experimental estimates of the local H(2) concentration were then obtained from the spatiotemporal fluorescence behavior and current measurements, and these were compared with finite element simulations accounting for electrolysis and subsequent convection and diffusion within the confined geometry. Local dissolved H(2) concentrations were correlated to partial pressures through Henry's Law and values as large as 8.3 atm were obtained at the most negative potential steps. The downstream availability of electrolytically produced H(2) in nanochannels is evaluated in terms of its possible use as a downstream reducing reagent. The results obtained here indicate that H(2) can easily reach saturation concentrations at modest overpotentials.     

乙基香兰素研究前景

报导了近几十年来国内外关于乙基香兰素的研究进展与动态,并简单介绍了本文作者在该方面所取得的研究成果,参考文献33篇。     

Reactions in droplets in microfluidic channels

Fundamental and applied research in chemistry and biology benefits from opportunities provided by droplet-based microfluidic systems. These systems enable the miniaturization of reactions by compartmentalizing reactions in droplets of femoliter to microliter volumes. Compartmentalization in droplets provides rapid mixing of reagents, control of the timing of reactions on timescales from milliseconds to months, control of interfacial properties, and the ability to synthesize and transport solid reagents and products. Droplet-based microfluidics can help to enhance and accelerate chemical and biochemical screening, protein crystallization, enzymatic kinetics, and assays. Moreover, the control provided by droplets in microfluidic devices can lead to new scientific methods and insights.     

Conferences in Chemistry Held in 2022

Russian Chemical Bulletin -