Radiotracer techniques Isotopes

Imai, T., Guto, H., Matsumura, H., and Yasuda, S., 1998, Determination of the distribution and reaction of polysaccharides in wood cell-walls by the isotope tracer techniques. VII. Double radiolabeling of xylan and pectin in magnolia Magnolia kobus DC) and comparison of their behaviors during kraft pulping by radiotracer technique. J. Wood Sci. 44 106-110. 

Isotopic exchange is the best example of the power of radiotracer techniques in chemical research. Isotopic exchange reactions have no inactive analogies. A system with two states of an element in equilibrium apart from isotopic distribution can be studied ... 

High-specific activity radiotracers, produced by neutron activation, have been used with great success to study biochemical processes in the small animal model. For example, Se, having a specific activity of 1,000 Cig has been used to advance the discovery of dependent enzymes and other biologically important proteins. Trace-element and mineral nutrition are important aspects of human and animal health. NAA has been used to characterize a wide variety of samples for their elemental content. The basic nutritional requirement at the cellular level can be studied using NAA and radiotracer techniques. NAA is one of the important methods that has been used to study nutritional bio-availability and absorption of essential trace elements in the human using enriched stable isotopes. 

The need for increased reliability and analytical quality control has emphasized the usefulness of radiochemical methods for the certification of standard reference materials (SRM) [9], [22j. 23J. Radioanalytical methods are often suitable for homogeneity testing and di.stribution analysis of traces in SRMs. Activation analysis, radiotracer techniques, and isotope dilution analysis are becoming increasingly important for assessment of analytical quality. 

Ram KD, Tripathi R (1990) Study of iodide- iodate isotopic exchange reaction in a few eutectic melts by radiotracer technique. Appl Radiat Isot 41 879-885, extrapolated... 

A most important technique which has been developed as an extension of the isotope dilution principle is that of radioimmunoassay (RIA). Analyses by this method employ substoichiometric amounts of specific binding immuno-chemical reagents for the determination of a wide range of materials (immunogens) which can be made to produce immunological responses in animals such as sheep or rabbits. It is possible to combine the specificity of an immunochemical reaction with the extreme sensitivity of radiotracer detection. Analytical methods based upon these principles have achieved wide applicability in the determination of organic compounds at trace levels. 

The use of radiotracers is an excellent technique for measuring the solubility product constant of sparingly soluble salts or for making other studies of substances present in low concentrations. Another very important and classic example of the use of radiotracers is that of studying the occurrence and properties of isotopic exchange reactions—reactions of the type... 

The isotope 40K can be analyzed in natural water samples with the Cherenkov counting technique.2 3 Because of the lack of a suitable radiotracer for K and the similarity between the chemistries of rubidium and potassium, 86Rb can be used as a tracer for K.4 Also, thermal ionization mass spectrometry (TIMS) has been used to determine 40K in environmental samples. The interference of mass 40 can be solved by double spiking with 43Ca/48Ca the procedure for the routine high-precision isotope analysis of the K-Ca system will then be free of Ca fractionations.5... 

Gel electrophoresis (GE) is a common separation technique in protein analysis and it has also been used for the speciation of metals bound to proteins [86]. In most applications, metals have been detected by autoradiography, limiting the studies to those elements for which a relatively stable radionuclide exists [87]. As an example, 75Se radiotracer allowed Se to be detected after two-dimensional GE (2-DE) separation [88]. Owing to the high sensitivity and isotopic capability of ICP-MS, this technique has been proposed as the detection tool of choice for elements in gel. The efbcient transport of the sample from the protein spot on gel to plasma has been achieved by laser ablation (LA) [89, 90] and electrothermal (ET) atomization [62, 91] techniques. The... 

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