Nuclear analytical techniques isotopic analysis

Filby RH (1995) Isotopic and nuclear analytical techniques in biological systems a critical study. Part IX. Neutron activation analysis (technical report). Pure Appl Chem 67 1929-1941. 

Analysis of a metallodrug in a biological tissue is a challenging task in analytical chemistry, primarily because the traditional methods used are usually indirect and semi-quantitative to a large extent, and are unable to visualize the metal ions in vivo. Advanced nuclear analytical techniques, such as X-ray fluorescence, neutron activation analysis. X-ray emission. X-ray absorption near-edge structure spectroscopy, nuclear magnetic resonance, and isotope tracing/dilution techniques offer some means by which elemental distribution, oxidation states, and species structural information can be studied. ... 

Applications The application of the isotope dilution technique is especially useful in carrying out precise and accurate micro and trace analyses. The most accurate results in mass spectrometry are obtained if the isotope dilution technique is applied (RSDs better than 1 % in trace analysis). Therefore, application of IDMS is especially recommended for calibration of other analytical data, and for certification of standard reference materials. The technique also finds application in the field of isotope geology, and is used in the nuclear industry for quantitative isotope analysis. 

In spite of the excellent capability and advantages (high selectivity and sensitivity) of RIMS for the ultratrace analysis of isotopes with naturally rare abundance in environmental, geological, medical and nuclear samples, no commercial instrumentation is available to date. In contrast to AMS and RIMS as mono-elemental (element-specific) analytical techniques, ICP-MS and LA-ICP-MS possess, in analogy to GDMS and SIMS, have the ability for multi-element analysis and thus could have the widest fields of application. 

Inevitably developments in all fields of analytical chemistry find their applications to the problems of the chemist in the field of petroleum. Thus ion exchange, microwave techniques, nuclear resonance, radioactive isotopes, activation analysis, high frequency vibrations, and other developments of fundamental research should find applications in the field of petroleum analysis. 

Atomic absorption offers a more practical opportunity for determining isotopic composition than atomic emission. Useful reviews of the possibilities of the technique have appeared in two books [233, 234]. Isotopic analysis is in theory possible provided that highly enriched isotope sources are available, the absorption line width available is less than the isotopic displacement and for a given isotope the nuclear spin hyperfine components must be partially resolved from the other isotopic components of the absorption line. In the simplest possible case, for an element with two isotopes, the lamp is prepared from the first isotope and only this isotope in the atom cell will absorb the radiation. The procedure can then be repeated with a lamp prepared with the second isotope. Effectively this is an extension of the impressive selectivity of atomic absorption, because of the classic lock and key effect, treating the different isotopes as different analytes. 

Thermal ionization mass spectrometry has been used extensively in the geological nuclear and analytical sciences for stable isotope measurements A new technique resonance ionization mass spectrometry offers a comprehensive approach to sensitive and selective elemental and isotopic analysis Recent developments in thermal and resonance ionization mass spectrometry are reviewed) and specific applications of the technology to zinc and calcium metabolism studies and to trace element analysis of foodstuffs are summarized ... 

The operation, since 1945, of nuclear reactors has made available radioisotopes of most elements. The isotopes are useful in a variety of chemical investigations, including those concerned with solubility, diffusion, reaction mechanism and structure. They have given rise to new analytical techniques, such as isotopic dilution and radioactivation analysis. In industry also, they have a wide and rapidly expanding application. All this is made possible by the ease with which small quantities of the nuclides can be detected, often remotely, and quantitatively determined by commercially available and easily operated equipment. 

Nevertheless, the technical and scientific achievements of nuclear forensics analysis are impressive. The ability to locate and detect minute amounts of uranium in a single particle in a swipe samples that may contain copious amounts of dust and soil particles is quite amazing. The fact that this individual particle may be singled out and its morphology, elanental, and isotopic compositions determined is indicative of the progress of analytical techniques. 

In non-nuclear teehniques, isotopes of the same element generally eaimot be distinguished, while in nuclear techniques, specific isotopes are measured instead of elements. Therefore, direct quantitative information on the associated elements ean be obtained since poly-isotopic elements have eonstant isotope ratios. Further, isotopes of a given element may be diseriminated therefore, analytieal information may be obtained by using elements enrlehed In respeet to a partieular stable isotope or labelled with a radioisotope, e.g. in isotope dilution analysis. In addition to analytical information, isotope studies may also yield kinetie and mechanistic information. 

The radiochemical methods of analysis to be discussed in this chapter will be divided into two groups for convenience tracer methods will be defined as those methods where the radioisotope is introduced into the analytical technique independently of the sample, and activation methods those where the radioisotope is incorporated into the sample by nuclear reaction. The different types of method may each have advantages in a particular situation, depending upon the availability of particular isotopes, the concentration at which the method is to be applied, and the instrumental facilities available to the individual analyst. 

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