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.     

New Complexing Polymer Aminothioether Sorbents in the Analytical Control of Recyclable Metal-Containing Raw Material of Rare and Noble Metals

The development and use of thioether sorbents for the separation and preconcentration of metals from aqueous solutions are described. The possibilities of initial polymer thioethers in selective preconcentration and the acceleration of sorption through the introduction of nitrogen-containing groups into thioethers are considered. The dependence of the selectivity of sorbents on the nature of radical at the nitrogen atom is revealed. The use of aminothioethers with different substituents at the nitrogen atom enables distinguishing the groups of noble metals, toxic elements of arsenic and selenium subgroups, and a number of nonferrous metals in the presence of large excesses of other elements. A high recovery of the elements to be determined into the sorption preconcentrate and the selectivity of the sorbents help to improve the accuracy of the analysis. Prospects for the use of aminothioethers are considered on an example of sewage waters. It is found that the extraction of small concentrations of elements from large volumes of solutions is more convenient to carry out in dynamics, for which powdered aminothioether sorbents are not suitable. To ensure a possibility of using aminothioethers in dynamics, a “snake in a cage” synthesis method is used, in which the inert granular support is modified with aminothioether moieties. The introduction of aminothioethers with different radicals at the nitrogen atom makes it possible to combine sorbents selective with respect to different groups of elements on one carrier and thus to create a universal sorbent with predetermined properties, aimed at extracting certain metals.     

Review of Analytical Methods for Atmospheric Oxidants Measurements

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.     

Spectrophotometric Methods for Determining Noble Metals

The main trends of the development of spectrophotometric methods for determining noble metals (NMs) are considered. One of these trends is the synthesis and study of new, highly sensitive and selective organic reagents for determining NMs in solutions and in solid phase. Another trend is the search for and development of new methodological approaches (techniques) and color reactions, including those that involve modified and immobilized reagents. The third trend includes the improvement of equipment and automation in FIA, CFA, derivative, rapid-scanning, and multiwavelength spectrophotometry. It also implies a new generation of instruments measuring the absorbance and reflectance of solid materials modified with organic reagents and with their NM complexes; microwave energy sources for the dissolution of samples, preparation of test solutions, and activation of photometric reactions; and multioperational analytical moduli for autoclave sample preparation with resistive heating. The present-day spectrophotometry can provide the determination of NMs in samples with concentrations from several to 10^–4% (photometry and differential photometry) and down to 10^–7% (test and sorption–spectroscopic methods based on photometry and diffuse-reflectance spectroscopy, including the use of chromaticity functions).     

磁性贵金属纳米催化剂

磁性贵金属纳米颗粒因具有高效的催化性能和可重复利用性而受到广泛关注。本文描述了磁性贵金属纳米颗粒的基本结构,介绍了磁性贵金属催化剂的基本组成部分,概括了磁性贵金属纳米颗粒的制备方法,阐述了国内外磁性贵金属纳米颗粒的创新研究,指出了发展磁性贵金属纳米催化剂亟待解决的问题,并对磁性贵金属纳米颗粒的应用前景进行了展望。     

Analytical Chemistry in the USSR

Abstract

In the USSR analytical chemistry is one of the most important of the chemical disciplines. Since its beginning as an independent part of the chemical research, analytical chemistry has developed as an integral part of the political economy, and serves the practical needs of industry, as well as being a theoretically well-founded science. Besides economically important problems like the analysis of the composition of sediments of raw materials, quality control in metallurgy and in the production of rare elements, analytical control in the chemical, pharmaceutical, nuclear-energy and semiconductor production are of importance, and furthermore, analysts develop their own theory, and success in many phases of development are related to a knowledge of other sciences, especially to physics, mathematics, general chemistry, metallurgy, biology, etc.     

Ferromagnetism Exhibited by Nanoparticles of Noble Metals

Gold nanoparticles with average diameters in the range 2.5–15 nm, prepared at the organic/aqueous interface by using tetrakis(hydroxymethyl)phosphonium chloride (THPC) as reducing agent, exhibit ferromagnetism whereby the saturation magnetization M_S increases with decreasing diameter and varies linearly with the fraction of surface atoms. The value of M_S is higher when the particles are present as a film instead of as a sol. Capping with strongly interacting ligands such as alkane thiols results in a higher M_S value, which varies with the strength of the metal–sulfur bond. Ferromagnetism is also found in Pt and Ag nanoparticles prepared as sols, and the M_S values vary as Pt>Au>Ag. A careful study of the temperature variation of the magnetization of Au nanoparticles, along with certain other observations, suggests that small bare nanoparticles of noble metals could indeed possess ferromagnetism, albeit weak, which is accentuated in the presence of capping agents, specially alkane thiols which form strong metal–sulfur bonds.     

Analytical Chemistry in Poland

ABSTRACT

The paper presents the main achievements of analytical chemistry in Poland on the basis of papers published mainly in the last decade. The selection is somewhat arbitrary but should show the most important directions of research. The citations generally refer to papers published in regular journals. The following topics were discussed: general aspects, chemical methods and reagents, spectrophotometry, speciation studies, atomic spectrometry, electrochemical methods, chemo- and biosensors, chromatography and related techniques.

Short reviews on the history and present status of analytical chemistry have been published elsewhere^{1, 2} and this review is intended to present the more detailed overview of the recent fields of interest, based on some selected publications from the nineties. Such selection is obviously to some extent arbitrary and this is mainly based on information sent by colleagues from various centres. It seemed, however, necessary to indicate where appropriate, the roots and earlier achievements.     

Analytical Chemistry in Romania

Abstract

Until now there has been no attempt to write the complete history of analytical chemistry in Romania. Nevertheless, we consider it important that our young chemists learn about the history of analytical chemistry in our country, because you can never step forward if you disregard the past. Furthermore, scientists in other countries might find the history and current status of analytical chemistry in Romania of interest.     

Analytical Chemistry in Australia

Abstract

Analytical chemistry in Australia is alive, but its current development can be likened to that of a young and vigorous infant who needs assured supplies of food, a favourable environment and some sound guidance for growth and eventual maturity. That analytical chemistry exists in Australia and is healthy, has occurred despite the existence of most of the 19 universities in Australia! Sweden, with a population of 8.5 million, has 10 chairs in analytical chemistry in 5 main universities and analytical chemistry has been an acknowledged branch of chemistry at Swedish universities since 1960¹. Australia, with a population of 13.5 million and reasonably comparable standard of living and industrial development, has only one chair in analytical chemistry (at The University of New South Wales) in its 19 universities. However, 4 of the remaining universities (Newcastle, La Trobe, Tasmania and Queensland) have a strong interest in analytical chemistry, which is somewhat difficult to discern by the incorporation of analytical chemistry in either general chemistry or inorganic chemistry departments.     

Analytical Chemistry in France

Abstract

In this day and age it is not an easy task to describe in a few pages the current status of any scientific discipline. This is particularly difficult if one deals with a n area such as analytical chemistry in France which is on the upswing. The present wirteup is focused on developments in French universities since the war: we shall not deal with analytical chemistry in industry, even though chemical companies and the French Atomic Energy Commission have had a paramount influence on recent developments. Indeed, French analytical chemists are being educated mainly to serve the needs of industrial laboratories.     

Analytical Chemistry in Israel

Abstract

Analytical chemistry in Israel is not in as good a shape as one may wish. Several attempts have been made to instill interest in this branch of the profession among faculty members, practicing chemists and students, but no great stride forward can be recorded, and on the contrary, some set-backs must be noted. Nevertheless, analytical chemistry is practiced vigorously in several laboratories, and original Israeli contributions in this field have been noted by the international community of analytical chemists. It is on this background that the present survey is being presented.     

Analytical Chemistry in Russia

Analytical Chemistry in the former Soviet Union and Russia is considered. Areas of the present analytical science in the country are noted and significant achievements are mentioned. Important centers of the researches are listed and education in Analytical Chemistry is examined. Received: 7 July 1997 / Revised: 28 August 1997 / Accepted: 7 September 1997     

Education in Analytical Chemistry

Summary After pointing out the necessity of including philosophical aspects in the teaching areas of Analytical Chemistry, proposals are made of new definitions of Analytical Chemistry and considerations are given of samples as representatives of a collective and carriers of information. An idealistic curriculum is presented for discussion.Presented at Euroanalysis III conference, Dublin, August 20–25, 1978