四取代酞菁化合物的合成和光谱性质

以3(4)-硝基邻苯二腈为起始原料经过两步反应合成了α(β)-四苯氧基酞菁.通过谱学方法和元素分析表征了其结构,研究了中心离子和取代基位置对酞菁吸收波长、发射波长和荧光强度的影响.结果表明,取代位置对最大吸收波长、最大发射波长和荧光强度的影响较大,而中心离子对荧光强度的影响较大,可降低荧光强度甚至淬灭荧光.     

光谱法研究核固红-Cu2+-阿莫西林体系及其分析应用

利用阿莫西林与Cu2+络合导致Cu2+对核固红的荧光猝灭程度减弱的特性,建立了荧光增强分析法检测阿莫西林含量的新方法。讨论了体系的紫外-可见吸收光谱、荧光光谱以及酸度、试剂浓度、反应温度、反应时间和离子强度等因素对体系荧光强度的影响。在最佳实验条件下,荧光强度的增强程度与阿莫西林质量浓度呈线性关系,线性范围为0.40~15.0μg/mL,检出限为0.29μg/mL。考察了一些金属离子和药物赋型物对体系的影响。将方法用于市售阿莫西林胶囊分析,回收率在100.4%~103.4%之间。     

镝—钆—钛铁试剂体系荧光光度法测定镝

发现了钆对镝－钛铁试剂荧光体系的协同发光效应,研究了镝－钆－钛铁试剂协同发光体系的荧光光谱特性,确定了试验条件对体系荧光强度的影响。在镝－钛铁试剂荧光体系中引入适量钆,可使体系的荧光强度提高５０倍,用标准加入法测稀土样品中痕量镝可获得满意结果。     

离子对高效液相色谱荧光检测法测定四环素类药物

报道了利用Ａｌ＾３＋作为柱前衍生试剂,高效液相色谱分离荧光检测法检测测定甲环素类药物的新方法。探讨了四环素类药物－Ａｌ＾３＋络合物的衍生条件及其色谱分离条件对荧光强度的影响,３种药物的检出限达７０￣１５０ｐｇ。     

气体敏感试剂的处理

Aldrich提供了许多有用的气体敏感试剂。具体的有甲硼烷络合物、有机甲硼烷化合物、硼氢化物、格氏试剂、有机铝化合物、有机锂化合物和有机锌化合物等溶液。由于所有这些试剂都与水或氧反应,因此它们决不可暴露在大气中。大多数现代合成化学家都熟悉这些金属有机试剂,但是,因为这些化合物对气体敏感,而且容易引起自燃,就不太想用它们。他们总认为处理气体敏感试剂需要非常特殊的装置和很复杂的技术,而事实并非常常如此。气体敏感试剂可以分为两类:一类是与空气或水     

胆红素、铜离子与2,2′-联吡啶作用的光谱研究

基于2,2′-联吡啶芳杂环羟基化法,采用荧光光谱研究了胆红素与Cu2 的相互作用。探讨了胆红素与Cu2 反应生成羟自由基(.OH),2,2′-联吡啶发生芳杂环羟基化反应的过程和反应机理,产生的羟自由基导致无荧光的2,2′-联吡啶发生芳杂环羟基化,生成强荧光物质;加入自由基猝灭剂后,荧光强度的增强明显减弱。考察了试剂加入顺序、反应时间、酸度、Cu2 浓度、胆红素浓度,以及2,2′-联吡啶浓度等的影响。     

巯基棉分离-氢化物原子荧光光谱法测定中药中不同形态的砷

建立了巯基棉分离吸附-氢化物发生-原子荧光光谱法测定中药中不同形态砷的分析方法：在1mol／l盐酸介质中．利用巯基棉实现了As(Ⅲ)和As(Ⅴ)的分离。研究了试剂浓度、不同增感剂等对砷荧光强度的影响和砷(Ⅴ)的还原条件,利用本法成功地对5种中成药中的砷进行了形态分析。方法检出限为64．3ng／L,RSD为1．12％,回收率为90％～116％。     

反相高效液相色谱法柱后调节pH胶束增敏荧光检测四环素类药物的研究

研究了适于分离检测四环素类药物的高效液相色谱荧光检测方法。为提高分析灵敏度,使用了柱后调节ｐＨ技术。探讨了ｐＨ以及胶束浓度对荧光强度的影响。四种药物的检出限达８．０～７５．６ｐｇ的水平。     

氢化物发生-原子荧光光谱法测定中草药中不同形态的砷

本文建立了氢化物发生-原子荧光光谱法测定中草药方剂原生药、残渣、悬浮态及可溶态中的三价及五价砷的方法。研究了仪器的工作条件、试剂浓度及不同增感剂对砷原子荧光强度的影响和五价砷的还原条件，探讨了共存离子对砷测定的干扰及消除方法。利用本方法成功地对黄连解毒汤中的砷进行了形态分析。方法检出限为89．1ng／L，RSD为1．24％，样品加标回收率为91．1％～109．3％。     

酶催化动力学荧光法测定乙醇

利用醇脱氢酶(ADH)催化乙醇与氧化型烟酰胺腺嘌呤二核苷酸(NAD)反应的原理,通过测定还原型烟酰胺腺嘌呤二核苷酸(NADH)荧光强度的变化率得出其酶促反应速度,对应乙醇浓度而制得标准曲线,试样中乙醇含量由标准曲线求得,检出限为4.0×10-6mol/L。考察了试剂用量、pH、共存组分对测定的影响。该方法简便、快速、准确。     

Effect of surfactants on the fluorescence intensity of organic reagents

The effect of 45 surfactants on the fluorescence intensity of 12 organic reagents has been studied and discussed. It has been found that there is a marked enhancement in the fluorescence intensity of organic reagents with nonrigid structures and with phenyl groups closely located.     

Membrane Microreactors for the On-Demand Generation,Separation, and Reaction of Gases

The use of gases as reagents in organic synthesis can be very challenging, particularly at a laboratory scale. This Concept takes into account recent studies to make the case that gases can indeed be efficiently and safely formed from relatively inexpensive commercially available reagents for use in a wide range of organic transformations. In particular, we argue that the exploitation of continuous flow membrane reactors enables the effective separation of the chemistry necessary for gas formation from the chemistry for gas consumption, with these two stages often containing incompatible chemistry. The approach outlined eliminates the need to store and transport excessive amounts of potentially toxic, reactive or explosive gases. The on-demand generation, separation and reaction of a number of gases, including carbon monoxide, diazomethane, trifluoromethyl diazomethane, hydrogen cyanide, ammonia and formaldehyde, is discussed.     

稀土元素的原子吸收光谱分析研究(Ⅵ)——有机试剂中磺酸基对镱火焰原子化的影响

在空气-乙炔焰中,研究了有机试剂分子中磺酸基对镱原子化行为的影响.发现含磺酸基的有机试剂,无论其分子中有无键合原子,键合原子为氮或氧,对镱均具有显著的增感效应;试剂中磺酸基的数目影响其增感程度,而其相对位置基本上无影响.并初步探讨了有机试剂分子中磺酸基的作用机理.     

Fabrication and Visualization of Metal‐Ion Patterns on Glass by Dip‐Pen Nanolithography

Fluorescent self‐assembled monolayers (SAMs) are used as dip‐pen nanolithography (DPN) substrates for the fabrication of patterns of Ca²⁺ and Cu²⁺ ions. The driving force for the transfer of these ions from an atomic force microscopy (AFM) tip to the surface is their complexation to organic ligands on the monolayer. By means of fluorescent surfaces, the patterns can be visualized under a fluorescence microscope. We use a custom‐built atomic force fluorescence microscope (AFFM), a combination of atomic force and confocal fluorescence microscopes, to deposit the metal ions onto the sensing SAMs by DPN and to subsequently visualize modulations of fluorescence intensity in a sequential write–read mode.     

Studies towards understanding the mechanism of organic reagent enhancement in flame and plasma atomic absorption spectrometry

A series of organic reagents have been tested in atomic absorption measurement for signal enhancement of metal elements. Organic reagents like tetrabutylammonium bromide are demonstrated to enhance the absorption sensitivity to some specific elements such as calcium and chromium. A group of amines were found to have significant enhancement for chromium and calcium measurements. The function of organic reagents in flame and plasma atomic absorption spectrometry (AAS) was investigated in this work with emphases on mechanism of signal enhancement and interference suppression. An alternative mechanism of organic reagent enhancement in flame and plasma AAS has been suggested based on the experimental results obtained in this work. The reduction environments in flame and plasma produced by the organic reagents are considered as major reason for the signal enhancement.     

Quinolizinium salts as fluorescent probes for N-nucleophiles

Quinolizinium salts are effective fluorescent reagents for the detection of amines. A series of carbamylquinolizinium salts was synthesized to take advantage of the influence of the carbamyl group on the fluorescence of the heterocyclic aromatic system. The native fluorescence of carbamylquinolizinium derivatives is described. The polycyclic compounds exhibit intense fluorescence which can be measured for 10^?10?10^?11 M solutions. With the diphenyl derivatives, it is not possible to establish correlations between the Hammett parameters from different substituents and the fluorescence emission. The fluorescence of reaction products with piperidine is described; the emission intensity observed is highest for the polycyclic quinolizinium derivatives, which can be considered as the most appropriate for the detection of amines.     

Some Quantitative Aspects of Scanning Densitometry in High-Performance Liquid Chromatography

Abstract

The optimization of instrumental parameters that influence resolution and signal-to-noise ratios in the recording of thinlayer chromatograms by scanning densitometry are discussed. A standardized method of determining sensitivity and detectability is proposed and used to evaluate the performance of a Shimadzu CS-910 scanning densitometer. Fluorescence enhancement reagents are discussed as a method of improving sample detectability in the fluorescence mode. The influence of the sorbent medium on both the position and intensity of the fluorescence emission signal is discussed.     

Fluorimetric determination of boron with resacetophenone as a reagent

Summary A method has been developed for the fluorimetric determination of boric acid, which gives a blue fluorescence with resacetophenone in sulphuric acid or phosphoric acid medium. The method has the advantage that the reaction does not require much time, because the fluorescence intensity reaches its maximum immediately after mixing the reagents and does not also decrease with time. The intensity of fluorescence can be measured with a fluorimeter and the amount of boric acid determined from a calibration curve.     

金汞齐富集冷原子荧光测汞法的研究

本文介绍了一种用于测定汞的金汞齐富集热解系统。研究了该系统与冷原子荧光测汞仪联用的工作条件和干扰,在最佳条件下的检出下限为4×10~(-13)克汞,分析周期3分钟,相对标准偏差2.5%(1.5×10~(-9)克汞)。