Isotopes applications

It should be mentioned that the same kind of equations hold if stable isotopes are applied for labelling of the elements or compounds to be determined by isotope dilution analysis. In this application, isotope ratios are taking the place of specific activities and they are preferably measured by mass spectrometry. 

In agricultural research and application, isotopes and radiation play a part in so many fields and in so many ways that it is difficult to obtain a proper picture of their enormous importance. In laboratories isotopes are used routinely with an ever-increasing assortment of modern research aids. In emerging biotechnologies, which are used increasingly by scientists, isotopes are a basic tool without which research in molecular biology could not be done. 

Isotopes are involved today in virtually all areas of chemistry. The use of isotopes in archaeological chemistry is widespread and rapidly growing, with many different applications. Different isotopes are used with many different kinds of materials to answer a variety of questions. Some of these isotope ratios are listed in Table 4.1 along with additional information on their abundance in nature, the kinds of materials sampled, and the kinds of information obtained in archaeological applications. Isotopes of oxygen, carbon, nitrogen, and strontium isotopes are more commonly used in archaeological applications and are discussed in more detail in this chapter. 

Oven/iew Waters, Sediments, and Soils. Ion-Selective Electrodes Water Applications. Isotope Dilution Analysis. Liquid Chromatography Size-Exclusion Liquid Chromatography-Mass Spectrometry Mass Spectrometry Peptides and Proteins. Voltammetry Overview. 

See also Ion Exchange Overview Principles Ion Chromatography Instrumentation Ion Chromatography Applications Isotope Separatbn. Liquid Chromatography Ion Pair. 

See alsa Air Analysis Outdoor Air. Atomic Emission Spectrometry Microwave-Induced Plasma. Atomic Mass Spectrometry Inductively Coupled Plasma. Elemental Speciation Overview Practicalities and Instrumentation. Gas Chromatography Environmental Applications. Isotope Dilution Analysis. Isotope Ratio Measurements. 

Chiral Analysis of Amino Acids Biotechnology Applications Clinical Applications Food Applications Pharmaceutical Applications Isotope Separations... 

See also Gas Chromatography Overview. Ion Exchange Ion Chromatography Applications. Isotope Ratio Measurements. Liquid Chromatography Reversed Phase. Mass Spectrometry Mass Separation Stabie isotope Ratio. 

In all these applications, isotope ratio data are produced, which are interpreted on an absolute or relative basis and which have an impact on our daily life, whether this is in science (e.g., age of an artifact), in society (e.g., provenance of food), or in public safety (e.g., neutron shielding in nuclear power plants). To ensure that these data are reliable and accurate, some specific requirements have to be fulfilled. The main requirement is that all these measurement results are comparable, which means that the corresponding results can be compared and differences between the measurement results can be used to draw further conclusions. This is only possible if the measurement results are traceable to the same reference [25]. This in turn can only be realized by applying isotopic reference materials (IRMs) for correction for bias and for validation of the analytical procedure. Whereas in earlier days only experts in mass spectrometry were able to deliver reproducible isotope ratio data, nowadays many laboratories, some of which may even have never been involved with mass spectrometry before, produce isotope ratio data using inductively coupled plasma mass spectrometry (ICP-MS). Especially for such users, IRMs are indispensable to permit proper method validation and reliable results. The rapid development and the broad availability of ICP-MS instrumentation have also led to an expansion of the research area and new elements are under investigation for their isotopic variations. In this context, all users require IRMs to correct for instrumental mass discrimination or at least to allow isotope ratio data to be related to a commonly accepted basis. 

Gammagraphic weld inspection in the lower range of steel thicknesses has been done with Iridium and Ytterbium isotope sources throughout the past. The large majority of applications has been using Iridium due to the unfavourable economical parameters of Ytterbium, obviously with non-optimal results at thin wall inspections. 

Recently we have made available the isotope Selenium for non-destructive testing. These sources offer technical specifications as required by industrial applications and provide various advantages when compared with other radiation sources. 

To support them, therefore, immense activities are prompted both in pubh c private sectors with increasing importance on NDT. The particular application of radiography using Ir-192 isotopes for industrial production, construction maintenance of industries, power plants, oil and gas pipelines plants, railway, aviation systems, naval structures and vessels, etc is currently in the fore front for its reliabih ly, ease of application record keeping advantages. 

Krypton clathrates have been prepared with hydroquinone and phenol. 85Kr has found recent application in chemical analysis. By imbedding the isotope in various solids, kryptonates are formed. The activity of these kryptonates is sensitive to chemical reactions at the surface. Estimates of the concentration of reactants are therefore made possible. Krypton is used in certain photographic flash lamps for high-speed photography. Uses thus far have been limited because of its high cost. Krypton gas presently costs about 30/1. 

Europium has been identified spectroscopically in the sun and certain stars. Seventeen isotopes are now recognized. Europium isotopes are good neutron absorbers and are being studied for use in nuclear control applications. 

Troost and Olavesen investigated the application of an internal standardization to the quantitative analysis of polynuclear aromatic hydrocarbons. The following results were obtained for the analysis of the analyte phenanthrene using isotopically labeled phenanthrene as an internal standard... 

Three common quantitative applications of radiochemical methods of analysis are considered in this section the direct analysis of radioactive isotopes by measuring their rate of disintegration, neutron activation, and the use of radioactive isotopes as tracers in isotope dilution. 

One example of a characterization application is the determination of a sample s age based on the kinetics for the decay of a radioactive isotope present in the sample. The most common example is carbon-14 dating, which is used to determine the age of natural organic materials. 

The previous discussion demonstrates that measurement of precise isotope ratios requires a substantial amount of operator experience, particularly with samples that have not been examined previously. A choice of filament metal must be made, the preparation of the sample on the filament surface is important (particularly when activators are used), and the rate of evaporation (and therefore temperature control) may be crucial. Despite these challenges, this method of surface ionization is a useful technique for measuring precise isotope ratios for multiple isotopes. Other chapters in this book discuss practical details and applications. 

Although cold plasmas have benefits in removing interfering ions such as ArO+, they are not necessary for other applications where interferences are not a problem. Thus, in laboratories where a range of isotopes needs to be examined, the plasma has to be changed between hot and cold conditions, whereas it is much simpler if the plasma can be run under a single set of conditions. For this reason, some workers use warm plasmas, which operate between the hot and cold conditions. 

Accurate, precise isotope ratio measurements are important in a wide variety of applications, including dating, examination of environmental samples, and studies on drug metabolism. The degree of accuracy and precision required necessitates the use of special isotope mass spectrometers, which mostly use thermal ionization or inductively coupled plasma ionization, often together with multiple ion collectors. 

Many artificial (likely radioactive) isotopes can be created through nuclear reactions. Radioactive isotopes of iodine are used in medicine, while isotopes of plutonium are used in making atomic bombs. In many analytical applications, the ratio of occurrence of the isotopes is important. For example, it may be important to know the exact ratio of the abundances (relative amounts) of the isotopes 1, 2, and 3 in hydrogen. Such knowledge can be obtained through a mass spectrometric measurement of the isotope abundance ratio. 

Accurate, precise isotope ratio measurements are used in a variety of applications including dating of artifacts or rocks, studies on drug metabolism, and investigations of environmental issues. Special mass spectrometers are needed for such accuracy and precision. 

MS", application of successive mass spectrometric measurements n of them), particularly in linked scanning of m/z, which is the ratio of the mass (m) of an ion and the number of charges (z) on it. Older publications used m/e, but as e is the actual charge on an electron and not the number of charges on the ion, the use of m/e was abandoned, m/z. mass-to-charge ratio, a measure of molecular mass PDB. PeeDee Belemnite (a carbon isotope standard see VPDB)... 

Baillie, T.A., Stable Isotopes Application in Pharmacology, Toxicology and Clinical Research, Macmillan, London, 1978. 

The phenomenon of multiphoton dissociation finds a possible application in the separation of isotopes. For this purpose it is not only the high power of the laser that is important but the fact that it is highly monochromatic. This latter property makes it possible, in favourable circumstances, for the laser radiation to be absorbed selectively by a single isotopic molecular species. This species is then selectively dissociated resulting in isotopic enrichment both in the dissociation products and in the undissociated material. 

One of the first applications of this technique was to the enrichment of and "B isotopes, present as 18.7 and 81.3 per cent, respectively, in natural abundance. Boron trichloride, BCI3, dissociates when irradiated with a pulsed CO2 laser in the 3g vibrational band at 958 cm (vj is an e vibration of the planar, D j, molecule). One of the products of dissociation was detected by reaction with O2 to form BO which then produced chemiluminescence (emission of radiation as a result of energy gained by chemical reaction) in the visible region due to A U — fluorescence. Irradiation in the 3g band of BCls or "BCI3 resulted in °BO or BO chemiluminescence. The fluorescence of °BO is easily resolved from that of "BO. 

Many challenging industrial and military applications utilize polychlorotriduoroethylene [9002-83-9] (PCTFE) where, ia addition to thermal and chemical resistance, other unique properties are requited ia a thermoplastic polymer. Such has been the destiny of the polymer siace PCTFE was initially synthesized and disclosed ia 1937 (1). The synthesis and characterization of this high molecular weight thermoplastic were researched and utilized duting the Manhattan Project (2). The unique comhination of chemical iaertness, radiation resistance, low vapor permeabiUty, electrical iasulation properties, and thermal stabiUty of this polymer filled an urgent need for a thermoplastic material for use ia the gaseous UF diffusion process for the separation of uranium isotopes (see Diffusion separation methods). 

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