Determination of Elements

The determination of silicon has been reviewed in detail [663, 664]. The element can be determined as Si02 or Si02 + 12 MoOj by gravimetric analysis. Fig. 5.6 shows a simple apparatus for pyrametric silicon determination [665]. 

Other methods of gravimetric silicon determination are fusion with fuming sulphuric acid [667] or with a mixture of fuming sulphuric and nitric acids [668,669], and fusion with sodium peroxide, followed by determination as SiOj -1-12 M0O3 [670]. 

A Requisition tube for Si02, filled to 2/3 its volume (zone C) with asbestos and glass splinters 8 mm, length 30 cm. B Test vessel. D Ground glass connection from A to B. E and F Clamps on the rubber tubes. G Reducing glass tube. H Burner. 

For volumetric determination of silicon, it is convenient to convert organosilicon compounds to the hexafluorosilicon anion, SiF . Hexafluorosilicic acid is unstable and must be titrated directly after it is formed. In the presence of benzidine, organosilicons react with hydrofluoric acid in ethanol to produce hexafluorosilicic acid benzidine complexes which may be hydrolysed and titrated with an alkali hydroxide [671], 

In addition to the methods for these elements suggested in the preceeding section [666], it is essential to have a method for a rapid determination of carbon and hydrogen in those organosilicon compounds which contain sulphur or are likely to explode. Suitable apparatus for this purpose is sketched in Figs. 5.7 and 5.8 [672]. 

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Z. Marczenko, Separation and Spectrophotometric determination of Elements, Fllis Horwood Ltd., West Sussex, UK, 1986. 

Z. Marc2enko, Separation and Spectrophotometric Determination of Elements, Ellis Horwood Ltd., West Sussex, UK, 1986 E. B. SandeU, Colorimetric Determination of Traces of Metals, Interscience Publishers, New York, 1959. 

In developing theoretical problems he always thought about practical uses of results in the national economy. His theoretical and experimental results were applied to developing numerous methods of analytical determination of elements in complex natural and technical situations, and also he also used the principles for improving the university curriculum and to generate new special courses. 

The existing variety of means and methods of micro-element analysis is used worldwide for the determination of element contents in atmospheric aerosols when they ai e collected at aspiration filters, sediment and natural surfaces and biota objects where toxic substances migration can be observed. 

Recently test-methods of the analysis are widely used they differ by rapidity, cheapness, simplicity of detenuination and don t demand availability of the expensive equipment. These methods are used at the control of manufacture, in diagnostic labs, in field and domestic conditions etc. Test -technique have received special distribution in the analysis of objects of environment natural and sewages, soils, air. The improvement both existing and developing of new methods and techniques of test-determination of elements is an actual problem of modern analytical chemistry. 

DETERMINATION OF ELEMENT COMPOSITION OF HUMAN BLOOD SERUM BY ICP AES... 

Control of metalloid content in natural objects, foodstuff and pharmaceuticals is an important task for modern analytical chemistry. Determination of elements such as Arsenic is necessary for evaluation of object toxicity, since their content in environment may exceed MCL (maximum contaminant level), posing hazard to human health. Elements such as Selenium in definite doses are healthy, but in greater quantities they produce toxic effect. 

The goal of our research was the comparison of the elemental content in cut part of nail and the part of nail, which contacts with the soft tissues of finger, the determination of elemental concentrations in 20 nails of individual, the determination of the elemental distribution as a dynamic mechanism. 

The goal of present investigation is the continuation of the researches on the determination of elemental content in the specimens from Pazyryk graves and the comparison of the elemental interrelations between the all samples. In addition, it was performed the determination of elemental concentrations in hair and nails of contemporary people from Ukok Plateau. 

SSMS provides complete elemental surveys for a wide range of sample types and allows the determination of elemental concentrations with detection limits in the range 10-50 parts per billion atomic (ppba). 

Since the 1950s XRF has been used extensively for the analysis of solids, powders, and liquids. The technique was extended to analyze thin-film materials in the 1970s. XRF can be used routinely for the simultaneous determination of elemental composition and thickness of thin films. The technique is nondesuuctive, rapid, precise, and potentially very accurate. The results are in good agreement with other elemental analysis techniques including wet chemical, electron-beam excitation techniques, etc. 

In practice image quality is also reduced by use of high mass resolution and energy offset. Often, therefore, mass interference cannot he avoided. Determination of element distributions is possible by use of image processing tools for classification of mappings of different masses [3.53]. 

Z Marczenko, Separation and Spectrophotometric Determination of Elements, 2nd edn, Wiley, Chichester, 1986... 

X-ray emission spectrography developed in a way that made it convenient to segregate as light elements—elements ordinarily beyond reach of the method—those of atomic number lower than titanium. Hydrogen and helium are, of course, excluded because they emit no x-ray lines (1.19). In the early days of x-ray emission spectrography, its relative uselessness for the determination of elements between helium and titanium counted heavily against it in comparison with emission spectrography in the visible or ultraviolet. 

Heumann kg, Gallus SM, Radlinger G, and Vogl J (1998) Accurate determination of element species by on-line coupling of chromatographic systems with ICP-MS using isotope dilution technique. Spectrochim Acta 53B z73-287. 

Schauenburg H, Weigert P (1991) Determination of element concentrations in biological reference materials by solid samphng and other analytical methods. Fresenius Anal Chem 342 950-956. 

Ihnat M (1988) Biological and related reference materials for determination of elements. In McKenzie HA, Smythe LE, eds. Quantitative Trace Analysis of Biological Materials, pp 739-760. Elsevier Science Publishers, Amsterdam. 

Although elemental analysis (i.e. the determination of elements ranging from H to U) in a polymeric material is very common practice in the polymer industry, among polymer processors, research and application laboratories, and end-users, the analytical methods and protocols used are widely different and are not harmonised within the EC, let alone worldwide. Among the currently established 344 ISO methods for plastics, there are no ISO-approved methods available for... 

Trends in element analysis are multi-element (survey) analysis, lower concentration levels, micro/local element analysis and speciation (coupling with chromatography). An overview of the determination of elements in polymeric materials is available [7], Reviews on sample preparation for trace analysis are given in refs [8-10]. Quality assurance of analytical data in routine elemental analysis has been discussed [11], Organic analysis is obviously much more requested in relation to polymer/additive matrices than elemental analysis. 

Applications Table 8.58 shows the main fields of application of inorganic mass spectrometry. Mass-spectrometric techniques find wide application in inorganic analysis, and are being used for the determination of elemental concentrations and of isotopic abundances for speciation and surface characterisation for imaging and depth profiling. Solid-state mass spectrometry is usable as a quantitative method only after calibration by standard samples. 

Applications ICP-MS has become the technique of choice for the determination of elements in a wide range of liquid samples at concentrations in the ng L 1 to [igL-1 range. Typical applications of ICP-MS are multi-element analysis of liquids (even with high solid contents) element speciation by hyphenation to chromatographic techniques continuous on-line gas analysis multi-element trace analysis of polymers and trace analysis in high-purity materials. ICP-MS is routinely used for quality control purposes. 

Isotope dilution (ID) is a technique for the quantitative determination of element concentrations in a sample, on the basis of isotope ratios [382]. An important prerequisite for isotope dilution is the availability of two stable isotopes, although in some cases the use of long-lived radionuclides allows the application range to be further extended [420]. 

Although following similar nuclear reaction schemes, nuclear analytical methods (NAMs) comprise bulk analysing capability (neutron and photon activation analysis, NAA and PAA, respectively), as well as detection power in near-surface regions of solids (ion-beam analysis, IB A). NAMs aiming at the determination of elements are based on the interaction of nuclear particles with atomic nuclei. They are nuclide specific in most cases. As the electronic shell of the atom does not participate in the principal physical process, the chemical bonding status of the element is of no relevance. The general scheme of a nuclear interaction is ... 

The characteristics of radiochemical methods are well known [435]. An overview of the determination of elements by nuclear analytical methods has appeared [436]. Some selected reviews of nuclear methods of analysis are available charged particle activation analysis [437,438], instrumental neutron activation analysis [439-441] and ion-beam analysis [442]. 

De Neve et al. (2000) have carried out a feasibility study to investigate the possibilities and limitations of CPAA as a thin layer characterization method (rather than for the determination of elemental concentrations in bulk samples). The required experimental conditions are (a) that the surface layer containing the analyzed element is thinner (1 pm or less) than the range of the charged particles used and (b) that the substrate (i.e. the layer on which the thin layer is deposited) does not contain the element(s) to be analysed. 

Danzer K (1976) Spectrographic semiquantitative determination of element traces in thin layers without calibration (Russ.). Zh Analit Khim 31 2327... 

In this paper I discuss overall metallicity, a measure of the overall heavy-element abundance in the star, and direct determination of elemental abundances and abundance ratios of Fe, O, the a-elements Mg, Si, Ca, and Ti, and also the light elements Na and Al. 

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