Neutron activation analysis techniques

Neutron activation analysis techniques are frequently used for trace element analyses of coal and coal-related materials (Weaver, 1978). Precision of the method is 25%, based on all elements reported in coal and other sample matrices. Overall accuracy is estimated at 50%. Neutron activation analysis utilizing radiochemical separations (NAA-RC) is employed by investigators when the sensitivity for a particular element or group of elements is inherently low or when spectral interference for a given element in a specific matrix is too great to be detected adequately. This situation was more prevalent before the advent of Ge(Li) spectrometry when only low-resolution Nal(TI) detectors were available. 

Islam, M.T., Islam, S.A., Latif, S.A. Detection of arsenic in water, herbal and soil samples by neutron activation analysis technique. Bull. Environ. Contam. Toxicol. 79, 327-330 (2007)... 

K. Heydorn Validation of Neutron Activation Analysis Techniques Quality Assurance for Environmental Analysis, Quevauviller, Maier, Griepink (Editors), Elsevier, Amsterdam,... 

The analytic methods generally fall into two groups (1) those that do not require the destruction of organic materials in the sample and (2) those that require the elimination of interfering matter before the selenium content can be measured. X-ray fluorescence and some of the neutron activation analysis techniques do not require sample destruction, whereas spectrophotometry, GC, atomic absorption spectrometry, polarography, titration, spark source, MS, fluorometry, and other neutron activation analysis techniques require some degree of sample destruction. Fluorometry, atomic absorption spectrometry, and neutron activation analysis are the most frequently used methods. 

Heydoen K (1995) Validation of neutron activation analysis techniques. In Quevauviller PH, Maier EA and Griepink B, eds. Quality Assurance for Environmental Analysis, pp. 89-110. Elsevier, Amsterdam. 

Fritze, K. and Robertson, R. (1968). Instrumental and Radiochemical Neutron Activation Analysis Techniques for Protein Bound Trace Metals in Human Serum. J. Radioanal. Chem., 1. 463. 

With reference to a Chart of the Nuclides, discuss the various neutron-activation-analysis techniques that might be used to determine Ni at the mg level. What neutron sources could be used What nuclear reactions would be involved What are the relative advantages and disadvantages of the various approaches to this determination ... 

Anilkumar, R., AnUkumar, S., Narayani, K. et al. (2012). A comparative study of 232-Th and 238-U activity estimation in soil samples by ganuna spectrometry and neutron activation analysis technique, Radiat. Prot. Environ. 35, 14-16. 

Landsberger, S. and Kapsimahs, R. (2013). Comparison of neutron activation analysis techniques for the determination of uranium concentrations in geological and environmental materials, J. Environ. Radioact. 117,41—44. 

The great bulk of the work which has been done on neutron activation anal-ysis for iodine has dealt with natural iodine-127 ( I(n,Y) I), and the procedures described below are concerned primarily with that isotope. Because of the growing interest in the long-lived, fission-produced iodine-129 (1.57 x 10 y), the section is concluded with a method for the sequential analysis of low levels of iodine-131, iodine-129, and natural iodine in environmental samples based on chemical separation and neutron activation analysis techniques. 

Methods for iodine deterrnination in foods using colorimetry (95,96), ion-selective electrodes (94,97), micro acid digestion methods (98), and gas chromatography (99) suffer some limitations such as potential interferences, possibHity of contamination, and loss during analysis. More recendy neutron activation analysis, which is probably the most sensitive analytical technique for determining iodine, has also been used (100—102). 

MetaUic impurities in beryUium metal were formerly determined by d-c arc emission spectrography, foUowing dissolution of the sample in sulfuric acid and calcination to the oxide (16) and this technique is stUl used to determine less common trace elements in nuclear-grade beryUium. However, the common metallic impurities are more conveniently and accurately determined by d-c plasma emission spectrometry, foUowing dissolution of the sample in a hydrochloric—nitric—hydrofluoric acid mixture. Thermal neutron activation analysis has been used to complement d-c plasma and d-c arc emission spectrometry in the analysis of nuclear-grade beryUium. 

The chemical composition of particulate pollutants is determined in two forms specific elements, or specific compounds or ions. Knowledge of their chemical composition is useful in determining the sources of airborne particles and in understanding the fate of particles in the atmosphere. Elemental analysis yields results in terms of the individual elements present in a sample such as a given quantity of sulfur, S. From elemental analysis techniques we do not obtain direct information about the chemical form of S in a sample such as sulfate (SO/ ) or sulfide. Two nondestructive techniques used for direct elemental analysis of particulate samples are X-ray fluorescence spectroscopy (XRF) and neutron activation analysis (NAA). 

Atomic absorption spectroscopy of VPD solutions (VPD-AAS) and instrumental neutron activation analysis (INAA) offer similar detection limits for metallic impurities with silicon substrates. The main advantage of TXRF, compared to VPD-AAS, is its multielement capability AAS is a sequential technique that requires a specific lamp to detect each element. Furthermore, the problem of blank values is of little importance with TXRF because no handling of the analytical solution is involved. On the other hand, adequately sensitive detection of sodium is possible only by using VPD-AAS. INAA is basically a bulk analysis technique, while TXRF is sensitive only to the surface. In addition, TXRF is fast, with an typical analysis time of 1000 s turn-around times for INAA are on the order of weeks. Gallium arsenide surfaces can be analyzed neither by AAS nor by INAA. 

All the techniques discussed here involve the atomic nucleus. Three use neutrons, generated either in nuclear reactors or very high energy proton ajccelerators (spallation sources), as the probe beam. They are Neutron Diffraction, Neutron Reflectivity, NR, and Neutron Activation Analysis, NAA. The fourth. Nuclear Reaction Analysis, NRA, uses charged particles from an ion accelerator to produce nuclear reactions. The nature and energy of the resulting products identify the atoms present. Since NRA is performed in RBS apparatus, it could have been included in Chapter 9. We include it here instead because nuclear reactions are involved. 

Radioactive nuclei are used extensively in chemical analysis. One technique of particular importance is neutron activation analysis. This procedure depends on the phenomenon of induced radioactivity. A sample is bombarded by neutrons, bringing about such reactions as... 

In the modern forensic chemistry laboratory (Figure B) arsenic is detected by analysis of hair samples, where the element tends to concentrate in chronic arsenic poisoning. A single strand of hair is sufficient to establish the presence or absence of the element. The technique most commonly used is neutron activation analysis, described in Chapter 19. If the concentration found is greater than about 0.0003%, poisoning is indicated normal arsenic levels are much lower than this. 

Comparison of Various FNAA Techniques for Assay of Synthetic Octol Samples Precision of Single-Axis Rotation FNAA for Assay of Octol Plant Samples Fast Neutron Activation Analysis for Nitrogen in Explosives by... 

A modem technique for nitrogen detn is known as fast neutron activation analysis. Materials such as RDX are exposed to a high density fast neutron flux which converts the 14N content of the sample into unstable 13N. The N is detd by measuring the 13 N produced by the 14N (n, 2n) 13N reaction. This technique is extremely sensitive, but requires specialized instrumentation (Refs 44, 51 61)... 

A Del Electronics, Model ESP-100A, electrostatic precipitator was used for sample collection. Cigarette smoke particles were found to give approx the same particle distribution pattern on the collection filter paper as the gunshot residue, and since the smoke stains the paper, this provided a v rapid technique for optimizing operation conditions. With a flow rate of 15cfm and a corona current of 125 uA, the residue collects primarily on a narrow band across the sample paper. Samples were collected on Whatman No 1541 filter paper which lined the inside of the sample collection tube. The presence of this paper allowed air to flow only thru the center of the tube, so particle collection was made upon the filter paper exclusively. The filter paper samples were pelletized prior to neutron activation analysis... 

The apphed pretreatment techniques were digestion with a combination of acids in the pressurized or atmospheric mode, programmed dry ashing, microwave digestion and irradiation with thermal neutrons. The analytical methods of final determination, at least four different for each element, covered all modern plasma techniques, various AAS modes, voltammetry, instrumental and radiochemical neutron activation analysis and isotope dilution MS. Each participating laboratory was requested to make a minimum of five independent rephcate determinations of each element on at least two different bottles on different days. Moreover, a series of different steps was undertaken in order to ensure that no substantial systematic errors were left undetected. 

Neutron activation analysis (NAA) is a supreme technique for elemental analysis (Section 8.6.1). Other nuclear analytical techniques, such as PIXE (Section 8.4.2) and RBS, also find application in investigations of diffusion processes [445]. 

Thus we shall be concerned with properties that furnish information about the nature of the ligands, the oxidation state of the metal, and the geometry of the field of ligands. Techniques such as radio-isotope tracer studies, neutron-activation analysis, and electron microscopy are powerful methods for locating a metal within constituents of the cell and are particularly suited to heavy-metal rather than organic drugs but since they do not provide information about the chemical environment of the metal they will not concern us here. After each section below we shall give an example, not necessarily from platinum chemistry, where the method has been used with success in biochemistry. 

Neutron activation analysis (NAA) is a technique for the qualitative and/or quantitative determination of atoms possessing certain types of nuclei. Bombarding a sample with neutrons transforms some stable isotopes into radioactive isotopes measuring the energy and/or intensity of the gamma rays emitted from the radioactive isotopes created as a result of the irradiation reveals information on the nature of the elements in the sample. NAA Is widely used to characterize such archaeological materials as pottery, obsidian, chert, basalt, and limestone (Keisch 2003). 

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