Multielement standards for instrumental neutron activation analysis of biological materials

Standards for instrumental neutron activation analysis (INAA) of biological materials are proposed. The standards are multielement solid solutions in phenol-formaldehyde resole resin (PFR) moulded as pellets weighing 30 to 50 mg. The concentrations of trace elements in the standards are selected so that, firstly, they are commensurable with their concentrations in the biological materials and, secondly, that the analytical lines of each of the elements incorporated in PFR are resolved with the aid of modern equipment. The principal standard contains 21 trace elements from among those of greatest interest for INAA of biological materials. This standard is recommended for work on high-resolution equipment. At the same time, standards of simpler trace element composition have been prepared and studied which can be used in work on simpler equipment or in solving particular problems in determination of certain groups of chemical elements.     

Multielement determination in tobacco leaves by photon activation analysis

A nondestructive photon activation procedure with 30 MeV bremsstrahlung followed by high-resolution gamma-spectrometry has been applied to the multielement determination in tobacco leaves and commercial cigarettes. The elements determined by this method included essential minor elements such as Ca, Cl, K and Mg, essential trace elements such as Fe, Mn and Zn, and possibly toxic elements such As and Sb. The NBS Orchard Leaves could successfully be used as a comparative standard. The method is quite simple and gives good reproducible results for at least 12 elements.     

The determination of zirconium in biological materials by photon activation analysis

Non-destructive photon activation analysis with 30-MeV bremsstrahlung has been applied for the determination of zirconium in biological materials. The materials investigated were the NBS SRMs Orchard Leaves and Bovine Liver, and various tissues of rats. The detection limits of this method for a 2 h irradiation are 0.1 g for Orchard Leaves, 0.04 g for Bovine Liver and animal tissues. The zirconium contents of animal tissues obtained in this work appear to be significantly lower than the values reported earlier. New data on zirconium in the NBS SRMs are presented.     

Multielement comparison of instrumental neutron activation analysis techniques using reference materials

Several instrumental neutron activation analysis techniques (parametric, comparative, and k_o-standardization) are evaluated using three reference materials. Each technique is applied to National Institute of Standards and Technology standard reference materials, SRM 1577a (Bovine Liver) and SRM 2704 (Buffalo River Sediment), and the United States Geological Survey standard BHVO-1 (Hawaiian Basalt Rock). Identical (but not optimum) irradiation, decay, and counting schemes are employed with each technique to provide a basis for comparison and to determine sensitivities in a routine irradiation scheme. Fifty-one elements are used in this comparison; however, several elements are not detected in the reference materials due to rigid analytical conditions (e.g., insufficient length of irradiation or activity for radioisotope of interest decaying below the lower limit of detection before counting interval). Most elements are normally distributed around certified or consensus values with a standard deviation of 10%. For some elements, discrepancies are observed and discussed. The accuracy, precision, and sensitivity of each technique are discussed by comparing the analytical results to consensus values for the Hawaiian Basalt Rock to demonstrate the diversity of multielement applications.     

Multielement determination in floor sediments of the Japan Sea by nondestructive photon activation analysis

A nondestructive photon activation analysis with 30 MeV bremsstrahlung has been applied to the multielement determination in the floor sediments in a region of the Japan Sea. The abundances for 5 major and 11 trace elements were measured in several terrigeous and pelagic deposits, discussion being given on the results. Enrichments in certain trace elements, such as Mn, Ni and Co, were observed in the samples of pelagic areas, but to less extent relative to those of the mid-Pacific areas.     

Multielement neutron activation analysis of biological materials using chemical group separation and Ge(Li) gamma spectrometry

Neutron activation analysis (NAA) for the determination of some trace elements in biological materials is described. The method presented permits the simple and rapid determination of Se, Ag, Au, Sb, Pt (via¹⁹⁹Au), Hg, Co, Ni (via⁵⁸Co), Fe, Zn, Mo, Sn, Cr, Cd, Cu and As after radiochemical separation from Na, K, Cs, Rb and partially Br. For this purpose, postirradiation separation by extraction with mercury or zinc amalgam was used. Separation of gold by extraction with ethyl acetate or by precipitation with dimethylglyoxime was applied for the determination of gold and platinum in biological materials.     

Resonance activation analysis of biological materials

An istrumental method is developed for the determination of As, Br, Cd, I, Mg, Mo, Sb, Si, Sn and Sr in biological materials based on resonance neutron activation analysis. Samples were irradiated inside cadmium and boron shields with reactor neutrons and counted on Ge(Li) detector after a delay of about 5 min. The interfering activities of²⁴Na,³⁸Cl and⁵⁶Mn were significantly reduced particularly in the boron shield. The advantage factors of the various elements are compared for boron and cadmium shields. The method is especially useful for the determination of As, Cd, I and Sn.     

Multielement trace analysis by atomic absorption spectrometry and neutron activation analysis in biological matrices

According to calculations of NIX and others, the formation of superheavy elements might occur in heavy-ion reaction systems such as the one under investigation in the present work i.e.,²³⁸U+^63,65Cu at 9.6 MeV/nucleon. Since previous experiments have indicated that upper limits to the production cross-section for superheavy elements are extremely low, we have carried out two rather long irradiations of 27 hrs and 42 hrs, respectively, at the University of Manchester LINAC. The first run has already been reported on in the literature. In the case of the second run, after chemical separation into HgS, CdS, and La(OH)₃ fractions, the samples were assayed simultaneously and continuously over a period of 6 months for alpha-and spontaneous-fission activity, using Si surface-barrier detector. Each sample was at the same time mounted on mice, for the purpose of scanning for fission tracks at a later date. No indications from the data have so far been found that superheavy elements were produced.     

Multielement photon activation analysis of coal samples using a Compton suppressed Ge(Li) detector

Multielement photon activation analysis has been carried out using a Compton suppressed Ge(Li) detector. The irradiated samples were N.B.S. standard reference coals and ashes. An increase in sensitivity by as much as a factor of three is attainable for some elements and this is especially valuable when analysing coals with low trace metal concentrations like N.B.S. reference material 1635.     

On the resonance activation analysis of biological materials

The performance of B+Cd tilter in activation analysis of biological materials is briefly discussed and compared with that of a composite filter recently proposed.     

Multielement analysis of lichen by instrumental neutron activation analysis

Lichen (species Trypethelium Eluteriae) is analysed for different elements. Nondestructive instrumental neutron activation analysis is employed for the multielemental analysis. Gamma-ray spectrometry is used for the identification and quantitative estimation of elements. Concentrations of 24 elements are reported. Gamma-ray spectrum of the lichen irradiated for 16 hours, delayed for 10 days, and counted for 10 hours on a 50 cm³ coaxial Ge(Li) detector is given.     

Multielement instrumental neutron activation analysis of silver-copper coins

Neutron activation, applied to silver and copper based coinage, leads to a measure of the mean concentrations of major and 12 trace elements, even if their distribution is heterogeneous. The drawbacks of this activation method applied to such a matrix are shielding effects and high radioactivity of major elements. Both effects were avoided by accurately calculating the correction coefficients and by choosing the optimal working conditions. Analytical results obtained lead to a better knowledge of the chronology and origin of Armorican protohistorical coinage.     

The analysis of biological and environmental samples for lead by photon activation

Résumé On utilise le réaction photonucléaire²⁰⁴Pb(γ, n)²⁰³Pb pour doser le plomb dans des échantillons issue de milieux biologiques et de l'environment. En utilisant des échantillons déjà titrés en plomb par d'autres méthodes, on a jugé la précision des mesures convenable. En utilisant une séparation chimique soignée après l'irradiation, la quantité limite détectée est de l'ordre d'une dizaine de nanogrammes.      

An application of neutron activation analysis to biological materials

Fourteen trace elements (short-lived nuclides: Al, Br, Cu, Mn and V; long-lived nuclides: Ag, Au, Cd, Co, Cr, Fe, Sc, Se and Zn) in human eye tissues are determined simultaneously by non-destructive neutron activation analysis. The quantity of Al, Br, Fe, Se and Zn in the eye tissues (about 1 to more than 10 μg/g dry weight tissue) seems to be higher than that of other trace elements, although content of each trace element in individual tissue are scattered in a wide range. Conjunctiva, iris (+ciliary body) and choroid (+pigment epithelium) seem to contain larger amount of various trace elements than other eye tissues. From correlation studies it is evident that the relative distribution of 14 trace elements in various eye tissues are similar, and furthermore the content of trace elements in the eye tissues may be correlated in each of the three groups (group A: Cd, Fe, Se and Zn; group B: Al, Cr, Fe, Se and V; group C: Al, Au, Fe and Se).     

An application of neutron activation analysis to biological materials

Contents of 13 trace elements in human hair were determined by neutron activation analysis. The distribution patterns of mean values of elements were extremely similar in all groups, though the contents of elements were individually different in each group. Numerous elements in new-born infants of both sexes correlated with each other, especially with V at a 95% confidence level. Special characteristics of diseased infants were the high contents of Cl and the low contents of Cr. It is presumed that these facts are due to the imbalanced acid-base equilibrium and some abnormal metabolic systems in diseased bodies.     

Instrumental neutron activation analysis of Na in biological materials

Sodium contents in seven mixtures of biological materials from varying aliquants of wheat flour and oyster tissue were analyzed using the INAA (instrumental neutron activation analysis) method. The samples were activated in the thermal column (TC) of the 1 MW TRIGA reactor at our laboratory. To analyze and compare the measured results, the ratioa of the epithermal neutron flux to the thermal neutron flux was determined in the TC, the rotating rack (RR) and the pneumatic terminal (PT). Due to the negligible interferences of²⁴Mg(n, p)²⁴Na and²⁷Al(n, )²⁴Na to²³Na(n, )²⁴Na, the Na results were obtained with 97% accuracy and 99% precision. It is shown that the method is suited for accurately determining Na contents in 12 various biological materials, especially for the samples that are low in Na content. From the cadmium ratio measurements of Au (4.9 eV resonance of¹⁹⁸Au) and Sm (8 eV resonance of¹⁵³Sm), ratios ofa_e/₀ were determined at 0.0011, 0.052 and 0.053 in the TC, RR and PT activation positions, respectively.     

Charged particle activation analysis of phosphorus in biological materials

Charged particle activation analysis of phosphorus in biological materials using the³¹P (α,n)^34mCl reaction has been studied. Since^34mCl is also produced by the³²S (α,pn) and the³⁵Cl (α, α′ n) reactions, the thick-target yield curves on phosphorus, sulfur and chlorine were determined in order to choose the optimum irradiation conditions. As a result, it was found that the activation analysis for phosphorus without interferences from surfur and chlorine is possible by bombarding with less than 17 MeV alphas. The applicability of this method to biological samples was then examined by irradiating several standard reference materals. It was confirmed that phosphorus can readily be determined at the detection limit of 1 μg free from interferences due to the matrix elements.     

Instrumental photon activation analysis of environmental materials using the internal standard method

In order to study effective applications of the photon activation analysis using the internal standard method, determinations of Cr, Co, Ni, Zn, As, Rb, Sr, Y, Zr, Nb, Sb, Cs, Ba, Ce and Pb in two marine sediments as environmental materials have been examined by the use of a personal computer-based gamma-ray spectrometer equipped with a micro-robot for sample changing. In these determinations, some major and minor constituent elements in the samples were properly used as effective internal standards to check the roles with each other. As a result, it was demonstrated that accurate and precise determinations of the above 15 elements were achieved efficiently and favourably.     

Multielement neutron activation analysis of an iron ore

Multielemental analysis of an iron ore from the Kingdom of Saudi Arabia was carried out using Instrumental Neutron Activation Analysis (INAA) with Ge(Li) detectors. The spectra were analysed with the help of an off-line computer programme. Twenty five elements are observed to be present in the ore. The elements of major interest are Fe, Al and Ca with 51.5%, 3.6% and 2.2% concentrations, respectively.