Fluorine Oxidants in the Analytical Chemistry of Noble Metals

This review is devoted to the physicochemical fundamentals and analytical practice of the use of fluorine oxidants in the decomposition of various naturally occurring and in-process materials containing noble metals. The experience in the application of halogen fluorides, xenon fluorides, and potassium tetrafluorobromate to the analysis and certification of the most difficult to decompose samples with the total precious metal contents from clarke values to 100% was summarized. The advantages of fluoride analytical procedures over traditional methods were demonstrated by examples of the most refractory test samples.     

Design of Enzyme-like Complexing Polymer Sorbents and Metal-Polymer Complex Catalysts with Memory to Substrates

Summary: A new principle of design of enzyme-like complexing polymer sorbents and metal polymer complex catalysts has been developed. The principle is based on the use of memory of polymer composition and consists in conformational prearrangement of macromolecules of noncrosslinked complexing polymer favorable for sorbing metal ions and/or catalyzing substrate position followed by intermolecular crosslinking. It has been shown that prearranged polymer sorbents and catalysts demonstrate significantly improved sorption and catalytic properties.     

Preparation and Study of New Metal-Containing Polymer Compositions Based on an Alicyclic Polyimide

New film-forming metal-containing polymer compositions based on an alicyclic polyimide and on arylalicyclic copolyimides synthesized from tricyclodecene-, oxydiphenyl-, and benzophenonetetracarboxylic dianhydrides and oxydianiline in the presence of cobalt, nickel, iron, and copper salts in amide solvents were prepared, and their main properties were studied. Optimum synthesis conditions and compositions of metalcontaining composites with improved thermal, electrical, and other characteristics were found. The possibility of using the modified alicyclic polyimide films for fabricating integrated circuits by magnetron sputtering was examined. The samples prepared by sputtering of metals onto SPI-1 polyimide films with a chromium sublayer are characterized by high adhesion of the metal to the film surface.     

Role of Modern Analytical Chemistry in Material Analyses for Trace Metals

The trend in the modern analytical laboratory is toward lower and lower analytical concentration measurements. The analyst has a variety of analytical instruments and techniques in which to meet the ever growing need for lower concentration measurements with improved precision and accuracy. Techniques available to the analyst include flame and electrothermal atomization-atomic absorption spectrometry, inductively coupled plasma atomic emission spectrometry, inductively coupled plasma/mass spectrometry, laser enhanced ionization spectrometry, neutron activation analysis, spectrophotometry, isotope dilution mass spectrometry, X-ray fluorescence spectometry, electroanalytical, and chromatography. However, there is no analytical technique that is a panacea for all analytes in the modern analytical laboratory. Steps the analyst must consider to obtain the highest degree of precision and accuracy include the obtaining of a representative sample, the selection of the “best” analytical method, the preparation of the sample, the calibration of the instrumentation, the deciding on the level of effort for the chemical measurement and the evaluation of the data are discussed.     

Advances in the Synthesis of New Organic Reagents for the Determination of Noble and Heavy Metals

Results are summarized on the synthesis of reagents for the determination of noble and heavy metals (sulfonitrophenol M, sulfochlorophenolazorhodanine (Rhodazol KhS), chlorophenolazorhodanine (Rhodazol Kh), sulfobenzeneazorhodanines, p-phenolazo-3-aminorhodanine, benzeneazobenzeneazorhodanine, sulfochlorophenolazothiopropiorhodanine (tyrodine), and hexaoxacycloazochrom), methods for their purification and identification, the determination of the concentration of the active compound in reagents, and techniques for the storage of reagents and the preparation of working solutions.     

稀土高分子发光材料研究的新进展

介绍了稀土高分子发光材料的发光机理及其发展历程，对其合成方法以及研究方向进行了综述，着重阐述了掺杂型和键合型稀土高分子发光材料研究的最新进展，并对其发展方向和应用前景作了展望。     

新型有机硅聚合物冠醚的合成及其络合性能研究

通过双羟甲基 - 18-冠 - 6与烯丙基氯反应得到双烯丙氧甲基 - 18-冠 - 6,以之为原料 ,与不同量的含氢硅油加成制备出 5种新型有机硅聚合物冠醚 ,同时测试了它们对K+和Na+的络合容量。     

新型生物可降解医用高分子材料—聚酸酐

综述了新型生物的可降解医用高分子材料－聚酸酐的发展概况，包括聚酸酐的发展历史，分类，合成及应用，提出了今后的研究方向。     

金属材料分析方法的选择和施行第六讲金属材料中稀土元素的测定

1概述1.1稀土元素及其存在从元素周期系中的位置来看稀土元素属于第Ⅲ属的钪分属。原子序数从57到71的15种元素,在周期系中占据了一个特殊位置,因为这些元素是由镧开始的,因此常把它们总称为“镧系元素”。它们的同族元素钪和钇,在化学性质上与稀土元素十分相似,并且在自然界中也经常与镧系元素共生在一起,因此,通常把钪,钇与镧系元素放在一起研究。但钪的原子半径特别小,与镧系元素和钇的原子半径有明显差别,因而钪表现出许多独特性质。而钇则与镧系元素更加相似,因此,习惯上常把钇也包括在稀土元素之中。稀土元素在自然界的蕴藏量并不少,…     

Sorbents for Analytical Determination of Cesium-137 and Strontium-90 in Natural Objects

The problem of determination of small activities of cesium and strontium in natural waters can be successfully solved by as design of highly sensitive lowbackground devices as development of new efficient techniques of concentrating radionuclides from large volumes of natural waters. While the problem of cesium concentrating may be solved quite successfully by a number of sorbents,the strontium concentrating is rather complicated.     

Diffusion of Noble Metals,Zn and Ge in GaSb Single Crystals

Diffusion of Cu, Ag, Au, Ge and Zn in single crystal gallium antimonide has been carried out by measuring Hall effect according to van der Pauw, conductivity, energy dispersive X-ray (EDX) and surface electron microscopy. The best results have been obtained in excess of antimony. The resulting diffusion data in GaSb are diffusivity D_o, activation enthalpy Q, carrier density p and mobility μ at 300 K: Ag: D_o=1.8·10⁻⁴ cm² s⁻¹, Q=1.2 eV, p=6·10¹⁸ cm⁻³, μ=550 cm² (Vs)⁻¹ Au: D_o=6.6·10⁺³ cm² s⁻¹, Q=2.7 eV, p=5·10¹⁸ cm⁻³, μ=500 cm² (Vs)⁻¹ Cu: D_o=3.2·10⁺⁸ cm² s⁻¹, Q=2.7 eV, p=2·10¹⁸ cm⁻³, μ=150 cm² (Vs)⁻¹ Zn: D_o=9.2·10⁻² cm² s⁻¹, Q=1.8 eV, p=2·10²⁰ cm⁻³, μ=80 cm² (Vs)⁻¹ Ge: D_o=1.0·10⁻¹ cm² s⁻¹, Q=1.7 eV, p=1·10¹⁹ cm⁻³, μ=320 cm² (Vs)⁻¹. This revised version was published online in August 2006 with corrections to the Cover Date.     

Preparation,Characterization and Analytical Applications of a New and Novel Electrically Conducting Polymer

In this study, a glassy carbon electrode (GC) was modified with an electropolymerized film of 1‐naphthylamine (1‐NAP) with a subsequent overoxidation treatment in 0.2 M sodium hydroxide solution. This polymer p‐1‐NAPox film coated GC electrode was used for the selective determination of dopamine (DA) in the presence of a triple concentration of ascorbic acid (AA).These studies were performed using cyclic voltammetry and square‐wave voltammetry at physiological pH. p‐1‐NAPox shows an attractive permselectivity, a marked enhancement of the current response and antifouling properties when compared to a bare GC electrode activated in basic media. With a preconcentration time of 3 minutes at open circuit, linear calibration plots were obtained for DA in buffer solution (pH 7.4) over the concentration range from 1×10^?6–1×10^?4 M with a detection limit of 1.59×10^?7 M.     

金属材料分析方法的选择和施行第六讲金属材料中稀土元素的测定(续)

钇的离子半径介于镝与钬之间,因此它的性质更接近于重稀元素。当元素的价态发生变化时,离子半径也发生变化。例如三价铕离子的半径为1.13,而二价铕的半径就增加到1.2~1.3,这就与锶的离子半径(1.27)接近了。因此,二价铕离子的性质与碱土金属离子比较相似,因而,就有可能用硫酸锶来共沉淀铕,以富集微量的铕。表6-3中还列出了稀土元素三价离子的颜色,可作为鉴别的参考。1.4镧系元素的化学性质在1.2及1.3节中简要地提到了镧系元素的电子结构和价态的关系以及镧系收缩和原子半径,离子半径的递变规律。这些元素的上述性质和现象对它们的化学性质也…     

金属材料分析方法的选择和施行第六讲金属材料中稀土元素的测定(续)

2．2稀土-硅-镁铁合金中稀土总量的重量法测定(摘自上海材料研究所分析室的日常分析方法) (1)试样的溶解及硅的除去称取试样0．500 g置于铂皿中,加入浓硝酸3～5 mL,小心滴     

金属材料分析方法的选择和施行第六讲金属材料中稀土元素的测定(续)

（注5）各稀土（Ⅲ）离子定量萃取（萃取率大于99％）的酸度范围稍有不同,如镧（Ⅲ）为pH4．95～5．90,铈（Ⅲ）为pH4．95～5．75,钇（Ⅲ）为pH4．10～5．55等。照顾到所有稀土（Ⅲ）的萃取,选用pH4．95～5.55。     

金属材料分析方法的选择和施行第六讲金属材料中稀土元素的测定(续)

1.5镧系元素的物理性质1.5.1镧系元素的晶体构型镧、铈、镨三元素是具有六方密堆积(h.c.p.)和立方密堆积(c.c.p.)晶型的双晶形金属,元素钪是面心立方(f.c.c.)和六方密堆积晶型的双晶形金属,钐是斜方六面体晶形,铕是体心立方晶形,镱是面心立方晶形,其余稀土金属都是六方密堆积晶形。稀土金属大都具有同素异晶的构型,由于晶型的转变,使其与其它金属的作用复杂化。钕的熔点为1 016℃,但以前曾把它由六方晶系向体心六立晶系转变的温度(840℃)误作为该金属的熔点。1.5.2镧系元素的密度钪的密度为2.99 g·cm-3和钇的密度为4.47 g·cm-3。其余元素…     

金属材料分析方法的选择和施行第六讲金属材料中稀土元素的测定(续)

2．7．1．1偶氮胂ⅢС.Б.Саввин于1959年合成了偶氮胂Ⅲ,其化学学名为2,2’-[1,8-二羧基-3,6-二磺酸-2,7-萘双偶氮]二苯胂酸。为暗红色粉末,溶于水中呈紫红色溶液,易溶于氢氧化钠及碳酸钠等碱性溶液中,不溶于浓酸及乙醇、乙醚、丙酮等有机溶剂中。在稀的无机酸如硫酸、硝酸及盐酸中有一定的溶解度,但当浓度较高时,如在2 mol·L-1或更浓的盐酸中,将因