Applications of Neutron Activation Analysis

Applications of activation analysis are to be found in all the major fields where analytical chemistry is employed. Some of the unique properties of the method have rendered its contributions in the field of trace element analysis invaluable. 

Perhaps the greatest single difference between activation analysis and other trace element methods lies in the virtual freedom of the activation method from contamination after irradiation. While this is of obvious importance in all fields of trace element analysis, it is of particular importance in the biological field. If conventional analytical methods are used the first stages in the analysis often consist in the destruction of large amounts of organic matter with the attendant risk of loss and contamination. 

Infomation as to the fate of strontium in the animal and plant organism is of particular interest at the present time. Harrison and Raymond (33) developed a rapid method for determining the metabolism of strontium and barium without interference from calcium. After short irradiation in BEPO, samples were chemically treated and the isotopes were gamma counted using a scintillation counter. More recently strontium and barium have been determined in bone by Sowden and Stitch (95). Strontium at the 5-60 ppm level has been determined in animal tissue by Brooksbank, et al. (10) while Bowen (5) has determined strontium and barium in sea water and marine organisms. 

Activation analysis may be regarded as an alternative to tracer techniques in the study of trace element metabolism. The activation method does not suffer from the disadvantage of possible radiation damage to the biological system inherent in the use of radioactive tracers. A further disadvantage in the use of tracers has been pointed out by Harrison and Raymond (33). They state that while giving valuable information as to the relative retention and distribution of trace elements, no absolute information as to their excretion rates is obtained. 

The sensitivity of analytical methods for trace elements needs to be high, and ideally the reaction or property utilized should be entirely specific. The sensitivity of activation analysis is dependent on the element estimated and in many cases it is extremely high. Specificity is covered by three parameters, half-life of the nuclide produced, its maximum beta energy, and its gamma spectrum. 

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A. Harrison, AnalChem 41 (1969), 1396 8) V. Guinn et al, Applications of Neutron Activation Analysis in Scientific Crime Investigations , Gulf General Atomic Corp Rept GA-9807 (1970) 9) K. Pillay et al, Nuclear... 

Iieser et al. [628] studied the application of neutron activation analysis to the determination of trace elements in seawater. The rare earths included in this study were cerium and europium. The element concerned were adsorbed onto charcoal. Between 75% and 100% of the elements were adsorbed onto the charcoal which was then subjected to analysis by neutron activation analysis. Cerium (300 p,g/l) and europium (0.00082 pg/1) were found in North Sea water by this method. 

Table 5.11. Application of neutron activation analysis to the determination of metals in seawater... 

It was not until the application of neutron activation analysis (NAA) that the problem of overlapping sources could be tackled. NAA is a highly sensitive and essentially non-destructive technique, although samples have to be taken which remain radioactive for some time after analysis. The use of NAA in characterizing obsidian was first demonstrated in the early 1970s (Aspinall... 

An application of neutron activation analysis for the determination of inorganic ions in LB multilayers was reported. A special technique for the removal of... 

Guinn, V. P., Hackleman, R. P., Lukens, H. R. and Schlesinger H. L. "Applications of Neutron Activation Analysis in Scientific Crime Investigations" U.S.A.E.C. Report GA-9882, National Science and Technology Information Service, G. S. Department of Commerce, Springfield, Va., (1970). 

For example, activation of the elements H, Be, C, N, O, F, Mg, Al, Si, Ti by thermal neutrons is negligible or low, because the products of (n,y) reactions are stable ( H, C, N, O, 0, 25Mg, 2 Mg, 29Si, 30si, 49xi short-lived ( F, Mg, A1, Si, Ti) or very long-hved ( Be). Samples containing these elements as main components are very well suited to the application of neutron activation analysis (NAA). 

This paper has given in outline form the major considerations on which a successful application of neutron activation analysis should be based. The most effective applications of thia method have Involved close and continual interaction between the physicist or engineer and the analyst from the beginning of the project, in order to ensure measurements that are meaningful and lead to the solution of the problem being studied. Activation analysis is only one of many analytical techniques available for materials characterization its sensitivity, accuracy, simple physics, and nondestructive nature should make it an important contributor for years to come. 

A new type of ceramic membrane electrode that is selective for F" ions has been prepared by sintering LaFg, EuFj, and CaFz at above 1200 °C in an atmosphere of Hf The approximate determination of the F" ion concentration in polluted waters can be made by means of a F ion electrode in the presence of citrate ion however, for an accurate determination a photometric method was applied after separation of F by distillation. The probable composition of the La " -alizarin complexone (H4A)-F complex is said to be La(LaA)4F2. ° Alizarin fluorine blue 5-sulphonate is more soluble in water than the unsulphonated reagent the ternary La -F -complexone absorbs at 583 nm. The application of neutron activation analysis to the determination of fluorine has has been reviewed briefly by Verot and Jaumier. X-Ray photoelectron spectroscopy (p.e.s.) has been used to identify and to provide a quantitative estimate of CF3, CF2, and CF groups on the surface of fluorinated diamond. Proton and deuteron radiolysis of... 

Ehmann, W.D., Maerkesbery, W.R., Kasarskis, E.J., Vance, D.E., Khare, S.S., Hord, J.D. and Thompson, C.M. (1987) Applications of neutron activation analysis to the study of age-related neurological diseases. Biol. Trace Element Res., 13,19-33. 

Anonymous. 1968. International Symposium on the Application of Neutron Activation Analysis in Oceanography Brussels, June 17-22,1968. Institut Royal des Sciences Naturelles de Belgique, Bruxelles. 218 pp. [Nucl. Sci. Abstr. 25(8) 15535.]... 

Applications to neutron activation analysis constitute another important use of Cf neutron sources. Neutron capture in many elements forms radioactive species that then decay with highly characteristic gamma-ray emissions. This analytical procedure is very sensitive and specific, and is widely used for the analysis of trace elements. Neutron activation finds use in uranium borehole logging to make accurate determinations of the uranium concentrations in boreholes as little as 100 parts per million of UaOg can be detected by this procedure. Other industrial uses for Cf sources are in the continuous monitoring of the sulfur and ash content of coal on a moving conveyor belt at the rate of SO tons per hour. Batch analysis of the vanadium content of crude oil is still another application of neutron activation analysis. 

Johansen, 0. and Steinnes, E. Application of Neutron Activation Analysis for the Determination of Some Major Trace Components In Standard Serum. Pp. 427-436 of Nuclear Activation Techniques In the Life Sciences, 1972. Vienna International Atomic Energy Agency (1972). 27 22102... 

The analysis of cadmium concentrations in biological material is mainly performed with ICP-MS or A AS. ICP-MS attains lower limits of detection than A AS. In addition, electrochemical methods, NAA, and XRF can be applied. The predominant sample matrices include blood and urine, but also hair, saliva, and tissue are used. The application of neutron activation analysis and X-ray fluorescence enables in vivo measurements of cadmium. 

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