Application of neutron activation analysis to metallobiochemistry

Some typical applications of long-term/low-level exposure (LLE) is presented including in vivo LLE study on rats and in vitro experiments on some metal binding components as well as on cadimium binding protein.     

Characterization of household plastics for heavy metals using neutron activation analysis

Highly enriched concentrations of several heavy metals have been found in municipal solid waste incinerator (MSWI) ash. In an effort to identify possible sources of these metals in MSWI ash, a variety of disposable household plastic products was examined for heavy metal content. Using both thermal and epithermal neutron activation analysis (NAA) along with Compton suppression techniques, concentrations of several trace and heavy metals including Ag, As, Au, Ba, Br, Cd, Cr, Cu, Fe, Mn, Ni, Sb, Se, Sn, Sr, V, W and Zn were determined. Results indicate a wide range of concentrations for these elements, with large variations in plastics of similar color and intended use. As limits dealing with heavy metal content of consumer products are lowered, NAA techniques will provide a useful method for verification of product compliance.     

Substoichiometric extraction of metals and its application to the determination of heavy metals in environmental samples by neutron activation analysis

Solvent extraction as a technique for the separation of ionic solutes and the advantages and application of substoichiometric extraction in neutron activation analysis have been discussed. The application of this technique has been elucidated with reference to the determination of Zn, Cd and Hg in environmental samples. The decontamination factor, accuracy, precision, sensitivity and radiochemical purity of the separated fraction have been discussed.     

Atmospheric deposition of heavy metals in Norway studied by the analysis of moss samples using neutron activation analysis and atomic absorption spectrometry

In a study of the atmospheric deposition of trace elements in different parts of Norway, samples of the mossHylocomium Splendens were analyzed with respect to 28 elements. The determination of Cu, Zn, Cd, and Pb was carried out by atomic absorption spectrophotometry, while 24 additional elements were determined by instrumental neutron activation analysis. In samples from southernmost Norway, a substantially higher concentration was found for elements such as Pb, Sb, V, Cr, Cu, Zn, As, Se, Mo, Ag, and Cd than in samples from places located in the more northerly parts of the country. The results indicate that sources which are to the south and south-west of Scandinavia, contribute significantly to heavy metal deposition in Norway.     

Feasibility studies of neutron activation analysis with kilogram-size samples

Instrumental neutron activation analysis (INAA) can now directly be applied to samples with masses in the kilogram range. It enables the analysis of material which is considered to be not representative at the scale of the traditional analytical portion, but representative at much larger scale. Large sample INAA (LS-INAA) circumpasses various problems associated with sample-size reduction and homogenization. Examples of feasibility studies are given as on construction waste, contaminated soil, harbour sediment and recyclable material. Also the economics of this method of analysis is discussed. Received: 30 October 1996 / Revised: 3 April 1997 / Accepted: 16 April 1997     

Feasibility studies of neutron activation analysis with kilogram-size samples

Instrumental neutron activation analysis (INAA) can now directly be applied to samples with masses in the kilogram range. It enables the analysis of material which is considered to be not representative at the scale of the traditional analytical portion, but representative at much larger scale. Large sample INAA (LS-INAA) circumpasses various problems associated with sample-size reduction and homogenization. Examples of feasibility studies are given as on construction waste, contaminated soil, harbour sediment and recyclable material. Also the economics of this method of analysis is discussed.     

Application of neutron activation analysis to bone samples

Summary Neutron activation analysis technique, using Au as flux monitor, was applied to determine element concentrations of Ca, K, Na, Mg, Mn and Sr in certified reference material (NIST 1400 Bone Ash). The results were compared with those using comparative INAA and they were compatible. The same results were obtained using the recommended k₀ factors, in order to obtain the activation cross section as input in concentration for the same reference material. Some applications in the health area aiming clinical evaluation in bone samples of medium and small-sized animals were performed and the viability of using this methodology was discussed.     

Study on air pollution monitoring in Korea using instrumental neutron activation analysis

Trace elements in airborne particulate matter collected monthly at suburban and rural areas in Korea were analyzed by instrumental neutron activation analysis (INAA). Neutron irradiation of the samples was done at the irradiation hole (neutron flux 1·10¹³ n·cm^–2·s^–1) of the TRIGA Mark-III Research Reactor in the Korea Atomic Energy Research Institute. For the verification of the analytical technique, two reference materials, NIST SRM-1648 and NIES CRM-8, were chosen for analysis. The accuracy and precision of the determinations of the 40 elements were compared with the reference values. We used this method (1) to analyze 30 trace elements in airborne particulate matter collected monthly with the high volume air sampler (PM-10) at two different locations and (2) to confirm the possibility of using this method as a routine monitoring tool to find out environmental pollution sources.     

Elemental analysis of local soda samples using instrumental neutron activation analysis

Nigerian soda samples have been analyzed for major, minor and trace elements using instrumental neutron activation analysis. The following elements were determined; Na, Sm, U, La, Cr, Eu, Zn, Hf, Fe, Sc, Ba, Rb, Cs, Co, Au, Yb, Lu, Th, Ce, Zr, Se, As and Ta. The samples appear safe to use in human diet, although they may still require industrial purification to bring down the level of nonessential elements and those that could be toxic when present at high concentration.     

Rapid measurement of selenium in biological samples using instrumental neutron activation analysis

A rapid instrumental system for measuring selenium via 17 second^77mSe has been applied to the analysis of a wide variety of biological specimens encountered in biomedical research. The reliability and versatility of the method is documented for serum and animal tissue specimens. Analysis results for SRM 1577 bovine liver show excellent accuracy and precision.     

Non-destructive determination of aluminum in biological reference samples using neutron activation analysis

The non-destructive methods of thermal and epithermal neutron activation analysis have been employed to determine the aluminum concentration of seven National Institute of Standards and Technology certified biological reference materials. Through the judicious use of both thermal and epithermal neutron activation analysis using bare and boron-lined irradiation carriers, the major and minor contributions of the³¹P/n, /²⁸Al and of the²⁸Si/n, p/²⁸Al reactions, respectively, to the²⁷Al/n, /²⁸Al reaction could be corrected for explicitly. Based on replicate determinations precision of the analysis ranged from 2.5% for citrus leaves determined at the 75 ppm level to 18% for bovine liver measured at the 1 ppm level. Accuracy was demonstrated whenever possible by comparison to existing published data.     

Determination of trace elements and heavy metals in a lake sediment by neutron activation analysis

Twenty trace elements and heavy metals of Dalat lake sediment were analyzed by neutron-activation analysis at the ASTRAREACTOR. The elaborated method was also controlled by analyzing the reference material for lake sediment SL-1 of IAEA. It showed a good agreement with the certified values for most of the elements. The relative errors ranged from 1% to 25%.     

The stability of trace metals suspensions in heavy crudes as determined by neutron activation analysis

The importance of trace elements in petroleum has increased, since the role of nonhydrocarbon components has been recognized in the elucidation of the mechanisms of migration and origin of crudes. On the other hand, knowledge of trace elements in petroleum is also important in the refining and processing of crudes. In developing different instrumental analytical techniques for trace analysis of crudes, little attention has been devoted to the scatter of data due to poor sampling and to the proper nature of the matrix. In the present paper the results of the determination of 17 trace elements including Co, Zn, Fe, V, Ni, Mo, Ba, Cs, Au, Br, Se, Sc, As, Mn, La, Eu and Cu are presented. A multielemental neutron activation analysis in a purely instrumental form was performed on a homogenized sample and the results are compared to those obtained on the same sample after a seven month period. The results clearly show that the crude loses its induced homogeneous nature and that a standard heavy crude can not be stocked for comparison purposes. For the heavy asphaltene fractions, results of the analysis of the same trace elements are presented and the possibility of its use as a standard is discussed.     

Instrumental neutron activation analysis of geological and pedological samples. Further investigation of epithermal neutron activation analysis using monostandard method

A comparative study is presented on neutron activation analysis of rock and soil samples using whole reactor neutron spectrum and epithermal neutrons with both relative and monostandard procedures. The latter procedure used with epithermal neutron activation analysis of soil samples necessitated the use of the “effective resonance integrals” which were determined experimentally. The incorporation of the β factor, representing deviation of reactor epithermal neutron flux from 1/E law, is developed in the present work. The main criteria for the choice of one or more of the procedures studied for a given purpose are also indicated. Analysis of 15 trace elements, Ca and Fe in the standard Japanese granite JC-1 using monostandard epithermal neutron activation gave results in good agreement with the average literature values. This paper is dedicated to the 80th birthday of Professor Dr. Robert Klement, University of Munich.     

Instrumental neutron activation analysis of environmental samples using thek 0-standardization method

The use of thek ₀-standardization method in instrumental neutron activation analysis gives good accuracy and precision. The analysis time can be reduced drastically by employing software for thek ₀-standardization calculations. In this work samples were irradiated in a TRIGA reactor and the gamma spectrum was analysed by Sampo 90 and thek ₀-standardization by the KAYZERO/SOLCOI code (DSM Research). The efficiency measurement and the peak to total ratio at the reference and other geometries were measured and tested for their accuracy by analysing some reference materials. Reference materials such as SRM 1572 (Citrus leaves), SRM 1573 (Tomato leaves), SRM 1575 (Pine needles), IAEA Soil-7 (Soil) and SRM 1646 (Estuarine sediment) were analysed for the major, minor and trace element contents. The results were in good agreement with the certified or literature values. The recently released IAEA 140 (Sea plant homogenates) was also analysed for 28 elements.     

Investigations on the comparator technique used in epithermal neutron activation analysis

The possible extension of the comparator technique of reactor neutron activation analysis into the field of epithermal neutron activation has been investigated. Ruthenium was used for multi-isotopic comparator. Experiments show that conversion of the so-called reference k-factors—determined by irradiation with reactor neutrons—into k_epi-factors usable at activation under cadmium filter, can be evaluated with fair accuracy. Sources and extent of errors and their contribution to the final error of analysis are discussed. Based on the paper presented at the 2nd European Conference on Analytical Chemistry, 25–30 August, 1975, Budapest, Hungary.     

Accuracy in standards preparation for neutron activation analysis

Errors in preparing standards, especially multielemental standards, are extremely important if accurate results are desired from neutron activation analysis (NAA). It is often convenient to prepare standards for NAA from single or multi-element solutions which are then deposited onto (or into) a suitable matrix, such as filter paper or quartz vials. There are many potential sources of error in preparing single-element standards including: impurities and non-stoichiometric composition of the element or compound used to prepare the standard solutions; evaporative losses of solvent; inaccuracy of calibration, and imprecision of the pipettes used; moisture content of elements or compounds used; contamination from reagents, equipment, laboratory environment, or final matrix of the standard; instability of standard solutions (i.e., to losses via precipitation or adsorption), and losses of volatile elements during dissolution and/or irradiation. Additional sources of error in preparing multielement standards includes: instability of mixed, multielement solutions, and cross-contamination of one element by the addition of a second element. Procedures previously used by the author at NIST to prepare multielement standards with concentrations accurate to about one percent are described. Additional techniques needed to prepare multielement standards with accuracies better than 1 percent will be discussed.     

Instrumental neutron activation analysis of air filter samples

Résumé La mesure de traces d'éléments dans l'air ambiant a fait l'objet d'une attention accrue ces derniers mois, en raison d'un intérêt grandissant pour les dangers en puissance pour la santé, qui résultent de l'exposition prolongée à certaines substances toxiques. L'analyse par activation neutronique a été employée avec succès dans la recherche de traces d'éléments, et ce, pour un grand nombre d'études de l'environnement; elle semble convenir de fa?on idéale pour la détermination non-destructive multi-élémentaire de la composition de milieux de particules portées par l'air. Dans cet article, on rend compte des performances de l'analyse instrumentale par activation neutronique comme on le montre dans le cas de 40 échantillons d'air filtrées provenant d'une zone métropolitaine.      

Sample preparation for the analysis of heavy metals in foods

The analysis of foodstuffs for heavy metals continues to be an area of intense activity for analytical chemists. Methods of sample preparation are changing to allow a growing number of samples to be handled and to facilitate 'speciation' studies.