无机含氧酸的酸性与分子拓扑指数的关系

本文提出一种新的分子拓扑指数Ｙ＝δＲ（ｍ＋ｋ０．５ｍ）ｎ－０．５。Ｙ对２５种无机含氧酸呈现唯一性表征，并与其ｐＫ１显示高度相关性。用最小二乘法拟合ｐＫ１与Ｙ的线性回归方程为：ｐＫ１＝１２．２３－１．２２Ｙ，ｒ＝－０．９７９，并在０．０１显著水平下通过Ｆ检验     

5''''-硝基水杨基荧光酮荧光熄灭法测定微量钨

本文基于Ｗ（Ⅵ）－５′－硝基水杨基荧光酮（５′－Ｎ－ＳＡＦ）－Ｔｗｅｅｎ－８０体系的荧光熄灭效应，提出一种测定微量钨的新荧光方法。在０．２～１．０ｍｏｌ／Ｌ的硫酸介质中，在Ｔｗｅｅｎ－８０存在下，５′－Ｎ－ＳＡＦ存在两个激发峰，其激发波分别为λｅｘ１＝４７５ｎｍ，λｅｘ２＝５０５ｎｍ，发射波长为λｅｍ＝５２５ｎｍ。Ｗ（Ⅵ）与５′－Ｎ－ＳＡＦ形成１∶３的配合物。钨浓度在每２５ｍＬ０．２５～２．５μｇ范围内呈线性关系，检测限为每２５ｍＬ０．２５μｇ。本法灵敏度高，选择性好，不经分离可直接测定合金钢中的钨，结果满意。     

催化动力学光度法测定痕量铁的研究

本文研究了在稀硫酸介质中铁催化过氧化氢氧化胭脂红的褪色反应及其动力学条件，测定了反应级数和表现活化能，建立了测定痕量铁的新方法。该方法的检出限为０．２５ｎｇ／ｍＬＦｅ，线性范围为０～０．４μｇ／２５ｍＬＦｅ，方法简便、快速、灵敏度高。应用于水及食品中痕量铁的测定，结果满意。     

二甲苯蓝FF分光光度法测定微量亚硝酸根

研究了在稀盐酸介质中微量亚硝酸根与二甲苯蓝ＦＦ发生的亚硝化反应，建立了测定微亚硝酸极的新方法，方法的线性范围为０．２×１０＾－６～１５×１０＾－６ｇ／２５ｍｌＮＯ＾－２其Ｓａｎｄｅｌｌ灵敏度为９．１５×１０＾－１０ｇ／ｃｍ＾２，方法已用于水微量亚硝酸根的测定，并对反应机理进行了初步探讨。     

分光光度法同时测定中草药中的钼和铜

本文建立了在混合显色剂（ＰＦ＋ＰＡＮ）的胶束体系中，利用分光光度法同时测定中草药中的钼和铜。实验表明：在混合体系中，钼量在０～１０μｇ／２５ｍＬ，铜量在０～５０μｇ／２５ｍＬ的范围内符合比尔定律，ε′Ｍｏ＝９．２×１０４Ｌ·ｍｏｌ－１·ｃｍ－１；ε′Ｃｎ＝１．５×１０４Ｌ·ｍｏｌ－１·ｃｍ－１。该法用于中草药样品的分析，结果满意，回收率可达９２～１１１％。     

5′—硝基水杨基荧光酮荧光熄灭法测定微量钨

本文基于Ｗ（Ⅵ）－５′－硝基水杨基荧光酮（５′－Ｎ－ＳＡＦ）－Ｔｗｅｅｎ－８０体系的荧光熄来效应，提出一种测定微量钨的荧光方法，在０．２～１．０ｍｏｌ／Ｌ的硫酸介质中，在Ｔｗｅｅｎ－８０存在下，５′－Ｎ－ＳＡＦ存在两个激发峰，其激发波分别为λｅｘ１＝４７５ｎｍ，λｅｘ２＝５０５ｎｍ发射波长为λｅｍ＝５２５ｎｍ。Ｗ（Ⅵ）与５′－Ｎ－ＳＡＦ形成１：３的配合物，钨浓度在每２５ｍＬ０．２５～２．５μｇ范围     

混合表面活性剂存在下二溴羟基苯基荧光酮光度法测定痕量铜

研究了在氯化十六烷基吡啶（ＣＰＣ）和吐温－４０存在下，铜与二溴羟基苯基荧光酮（ＤＢＨ－ＰＦ）显色反应，结果表明，在ｐＨ６．０－７．１的六次甲基四胺－盐酸缓冲溶液中，铜与ＤＢＨ－ＰＦ形成１：１配合物，其最大吸收峰全于５７０ｎｍ摩尔吸光系数１．２×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，铜含量在０～６μｇ／２５ｍＬ范围内符合比尔定律，方法用于测定环境水标样及牛肝粉标样中的痕量铜。     

Ti（Ⅳ）—F^——邻硝基苯基荧光酮—氯化十六烷基吡啶四元体系显色反应…

本较详细研究了在Ｈ２ＳＯ４介质中，Ｔｉ（Ⅳ）－Ｆ＾－－ｏ－ＮＰＦ－ＣＰＣ体系水相光度法测定痕量钛的新方法。四元体系的最大吸收峰在５６５ｎｍ处，表观摩尔吸光系数为２．１×１０＾５Ｌ．ｍｏｌ＾－＾１．ｃｍ＾－＾１，Ｓａｎｄｅｌｌ灵敏度为２．２８×１０＾－＾４μｇＴｉ／ｃｍ＾２。钛含量在０－４μｇ／２５ｍＬ范围内遵宁比尔定律。方法用于土壤，粮食，牧草，蔬菜和中草药中钛的测定，结果满意。     

高效毛细管电泳—电化学法检测烟酰胺腺嘌呤二核苷酸

报道了一种测定烟酰胺腺嘌呤二核苷酸的毛细管电泳电化学检测方法。采用３０ｃｍ×２５μｍ的石英毛细管分离ＮＡＤＨ与脲酸，以微型碳糊电极测定经分离后的ＮＡＤＨ的含量。在ｐＨ７．５的磷酸盐缓冲溶液中，标准工作曲线的范围为１．０－１００μｍｏｌ／Ｌ；最代检测浓度为０．６０μｍｏｌ／Ｌ。     

二溴羟基苯基荧光酮荧光猝灭法测定Br^—

本文报道了以二溴羟基苯基荧光酮（ＤＢＨ－ＰＦ）为指示剂，在阳离子表活性剂ＣＰＣ存在下荧光猝灭间接测定Ｂｒ＾－的新方法。在０．６ｍｏｌ／ＬＨ２ＳＯ４介质中，Ｂｒ＾－和ＢｒＯ３＾－反应生成Ｂｒ２，Ｂｒ２与ＤＢＨ－ＰＦ（λｅｍ＝５２０ｎｍ）生成红色化合物，使体荧光猝灭。Ｂｒ＾－含量在０．２５－６．２５μｇ／２５ｍＬ范围内有良好的线性关系，检测限为０．２５μｇ／２５ｍＬ。该法灵敏度高，选择性好，用于合成海     

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。     

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.     

Gemini表面活性剂合成进展*

系统总结了近百种Gemini表面活性剂的合成路线和方法,并且按照其结构特点分门别类地进行比较和归纳,对今后Gemini表面活性剂的合成发展方向提出了一些看法,这对促进此类新颖表面活性剂的工业化进程将具有指导意义。     

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.     

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.     

Trends in education in analytical chemistry

Summary At the session of the WPAC of Fechem on education in analytical chemistry it was concluded that it is now essential to include chemometrics and basic knowledge of computers in all courses on analytical chemistry.

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Tendenzen in der analytisch-chemischen Ausbildung

Zusammenfassung Bei einer Tagung der WPAC über die Lehre auf dem Gebiet der analytischen Chemie wurde bei der Betrachtung neuer Aspekte festgestellt, daß vor allem Chemometrie und Grundkenntnisse in Computertechnik in die Ausbildung aufgenommen werden sollten.

     

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。     

钙与人体及临床

钙是宏量元素，是人体中含量较高的元素之一，体内99％的钙构成骨骼和牙齿以及维持骨骼结构，1％的钙调节人体重要生理功能。钙的含量过高或过低都与许多疾病有关，只有保持一种平衡状态，才能使机体处于正常环境。     

Recent progress in nitroxide-mediated polymerizations in miniemulsion

Recent developments in nitroxide-mediated polymerizations conducted in emulsion and miniemulsion have advanced the field across a range of both experimental and theoretical fronts. This article reviews progress in bicomponent initiating systems (including use of camphorsulfonic acid to enhance rate), unimolecular initiating systems, miniemulsions not requiring the use of volatile costabilizers, polymerization of acrylates, mathematical modeling and simulation, and theoretical understanding with regards to issues such as compartmentalization, preservation of polymer chain livingness, the role of aqueous phase kinetics and phase partitioning. These topics are discussed and analyzed to present an integrated portrait of the current status of nitroxide-mediated polymerizations in emulsion/miniemulsion and to identify the most pressing concerns, issues, and opportunities. To cite this article: M.F. Cunningham, C. R. Chimie 6 (2003).