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- Author or Editor: K. Masumoto x
- Chemistry and Chemical Engineering x
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Abstract
The internal standard method coupled with the standard addition method has been applied to the analysis of environmental materials, such as urban particulate matter, vehicle exhaust particulates and coal fly ash by photon activation. High-resolution gamma-ray spectrometry makes possible to use multi-internal standard gamma-rays, in order to crosscheck the analytical results obtained from each internal standard. It was ascertained that this method can provide not only accurate analytical results but also the information of homogeneity of samples, correlation of elements in the sample, loss or contamination in the preparation process.
Abstract
In order to study instrumental charged-particle activation analysis using the internal standard method, simultaneous determination of several selected elements, such as Ca, Ti, V, Fe, Zn, As, Sr, Zr and Mo, in oyster tissue, brewer's yeast and mussel has been examined by using the respective (p, n) reactions and a personal computer-based gamma-ray spectrometer equipped with a micro-robot for sample changing. In the above determination, constant amounts of Y and La were added to the sample and comparative standard as exotic internal standards. As a result, it was demonstrated that concentrations of the above elements can be determined accurately and precisely.
Abstract
Multielement determinations of coal fly ashes (NIST SRM-1633a and BCR CRM-38) have been carried out by instrumental photon activation analysis using 30 MeV bremsstrahlung and the internal standard method coupled with the standard addition method. In these determinations, some major and minor constituent elements in the samples were properly used as effective internal standards. As a result, it was demonstrated that concentrations of 18 elements were determined accurately and precisely. Furthermore, a similar multielement determination has also been examined using 20 MeV bremsstrahlung. In this case, it was proved that better results can be achieved, because all interfering reactions were eliminated completely.
Abstract
Charged particle activation analysis of phosphorus in biological materials using the31P (α,n)34mCl reaction has been studied. Since34mCl 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.
Abstract
As a new method, stable-isotope dilution activation analysis has been developed. When an element consists of at least two
stable isotopes which are converted easily to the radioactive nuclides through nuclear reactions, the total amount of the
element (xg) can be determined by irradiating simultaneously the duplicated sample containing small amounts of either enriched
isotope (y g), and by using the following equation.
Abstract
In order to study further the applicability of the newly developed stable isotope dilution method, simultaneous determination of Ca, Rb, Sr and Ce in three kinds of environmental materials has been tried by means of photon activation using isotopically enriched48Ca,87Rb,86Sr and142Ce as spikes. All determinations were demonstrated to be sensitive, highly specific and reasonably accurate.
A new internal reference method for activation analysis and its application
Determination of Ti, Cr, Ni and Zr in aluminium alloys by means of photon activation
Abstract
A new internal reference method for activation analysis has been developed. The method can be used effectively for special samples in which suitable elements as internal standards are absent and the self-shielding effect can be neglected. In this method, Wb g of element B as an internal reference is added to the sample which contains Wa g of element A to be determined, whereas the comparative standard is prepared by mixing only the element A and B in a known concentration ratio of W
a
*
/Wb. When the sample and comparative standard are irradiated by particles with the same energy distribution, even though both are irradiated separately by particles with different flux, Wa can be determined easily by the following equation.
Abstract
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.
Abstract
In order to demonstrate the usefulness of alpha-particle activation analysis, simultaneous determination of P, Cl, K and Ca in commercially available control serums has been studied fundamentally. After thick target yield curves of radionuclides produced from the element to be determined were measured as a function of alpha energy together with those of the interferences, an optimum working standard for the present experiments was provided by applying the internal standard method to a human serum under the most suitable bombardment conditions. Then, the concentrations of the above four elements in several control serums were determined efficiently and reasonably by ordinary alpha-particle activation analysis.
Abstract
In order to achieve the highly accurate and precise multielement determination in environmental materials, the usefulness of the comparative standard provided by the processing method proposed previously for soil samples has been re-examined using calcareous loam soil, light sandy soil and river sediment as unknown samples. As a result, it was also demonstrated that concentrations of 15 trace elements in each sample can be determined effectively and reasonably.
