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At least 19 recordsLinked to original sources
PubMed1979

Study on trace impurity elements in highly purified iron and aluminum by neutron activation analysis.

Activation analysis was carried out on the purified iron and aluminum to study the behavior of trace impurities on purification process, and to estimate the purity of the purified samples. Thermal neutrons with high Cd ratio through D2O column or graphite column were used for the activation of samples to reduce the interference effects by fast neutrons, the reactions, (n, p) or (n, a), from matrix elements. On the zone refined aluminum, the segregation of impurity elements was cleary observed. In the case of iron, decrease of impurity content was confirmed on superposing the various purification processes.

Aluminum↗
PubMed1978

Measurement of chromium VI and chromium III in stainless steel welding fumes with electrom spectroscopy for chemical analysis and neutron activation analysis.

Electron Spectroscopy for Chemical Analysis (ESCA) was explored as a means of studying the oxidation state of chromium in SMAC (coated electrode) stainless steel welding fume collected on Nucleopore filters in the laboratory. Chromuim VI and III (as a percent of the total chromium) obtained from ESCA analysis was applied to results from Neutron Activation Analysis (NAA) to yield an average of 69 microgram chromium VI per sample. Diphenylcarbazide/atomic absorption (DPC/AA) results are reported for samples submitted to an industrial laboratory. Possible chemical species and solubility of chromium VI in stainless steel fumes is discussed in light of analogy between the SMAC process and the manufacturing process for chromates.

Air Pollutants↗
PubMed1979

Cadmium analysis by radiochemical neutron activation analysis.

Radiochemical neutron activation analysis (RNAA) has been routinely used at the National Bureau of Standards to analyze Cd in a variety of environmentally important matrices. The method used to separate Cd from other neutron-activated products is solvent extraction. Zinc diethyldithiocarbamate [Zn(DDC)2] in chloroform will quantitatively extract Cd from an aqueous solution over a pH range from 1 to 12. In addition to the extraction of Cd, Zn(DDC)2 will also extract Cu, which can interfere with the Cd analysis by producing a high background level of radiation. This can be avoided by first extracting with Bi(DDC)3 in chloroform which removes Cu, but not Cd. Copper concentrations can, therefore, be determined in addition to Cd. This two extraction radiochemical separation procedure is very versatile and is often used as part of a larger multi-element analysis scheme. One such scheme involves the use of an inorganic-ion exchanger, Hydrated Manganese Dioxide (HMD), to retain As, Sb, Se, and Cr prior to extraction. The eluted fraction is then extracted with Bi(DDC)3 to remove Cu, and then with Zn(DDC)2 to remove Cd.

Activation Analysis↗
PubMed1991

The determination of platinum in biological tissue by instrumental neutron activation analysis.

Neutron activation analysis was used to determine platinum in the tissues of rats that had received doses of the tumor chemotherapy agent cis-Pt. Two elements causing spectral interference were identified as 47Sc from 46Ca, a natural component of tissue, and tin (117mSn), an element introduced inadvertently during necropsy and sample work-up. A protocol was devised to correct for interference, using emission lines from 47Ca and 113Sn, respectively, with appropriate consideration for relative detector efficiencies, decay times and half-lives.

Animals↗
PubMedDate not supplied

Determination of inorganic components in Brazilian medicinal plants by neutron activation analysis.

Instrumental neutron activation analysis (INAA) has been applied to multielemental determinations of medicinal extracts obtained from the plants. Cordia Verbenacea DC, Folidago Microglossa DC, and Petiveria Alliacea. Concentrations of the elements Al, Br, Ca, Cl, Co, Cs, Fe, K, La, Mg, Mn, Na, Rb, Sb, and Zn have been determined in dried extracts of these herbs by short and long irradiations under a thermal neutron flux of 10(11)-10(13) n/cm2s in the IEA-R1 nuclear reactor. The NBS Tea Leaves (1572) and NIES Pepperbush (1) reference materials were analyzed simultaneously with the plant extracts. The results obtained in these analyses have shown a good accuracy and reproducibility of the method. The relative errors and the relative standard deviations were less than 10% for most of the elements analyzed.

Brazil↗
PubMed1978

Determination of certain selected bulk and trace elements in the bovine liver matrix using neutron activation analysis.

Effective utilisation of neutron activation analysis (NAA) for the elemental analysis of biomedical samples with or without a radiochemical separation, especially when optimal Ge(Li) well type detectors are employed for the acquisition of complex spectra, is demonstrated by determining normal values for 25 elements in bovine liver. Optimal conditions for the determination of Ag, Br, Cl, Co, Cs, Fe, I, K, Mn, Na, P, Rb, Sb, Sc, Se and Zn with the aid of instrumental thermal neutron activation analysis (INAA) by varying the irradiation and decay time are presented. Where INAA was inadequate, simple post irradiation separation based on ion-exchange has been used to determine such elements as Au, Ca, Cd, Ce, Cr, Cu, La, Mo and W. Results from the IAEA intercomparison run for animal muscle (H-4) are also given. The influence of sample size with respect to within-tissue variation of the bulk and trace elements in liver and the contamination of liver samples from the interfering components such as residual blood are also discussed.

Activation Analysis↗
PubMedDate not supplied

Charged-particle activation analysis of biological material.

Charged-particle activation analysis offers a number of interesting possibilities for the determination of trace elements in biological material. It allows the determination of those elements that are difficult or impossible to determine by neutron activation, such as Li, B, Al, Si, V, Cr, Ni, Cd, Sn, Tl, and Pb. Up to now, protons have been successfully applied to samples of both vegetal and human origin. A number of difficulties have to be overcome, one of which is excessive heating of the samples owing to the limited range of the charged particles, thus giving rise to a high energy deposition in a small volume. Moreover, the sample composition has to be known to allow the calculation of the range of the particles. An interesting alternative has been proposed using an internal standard together with a standard additions procedure. Proton activation analysis was tested on a wide variety of reference materials, giving evidence that accurate results can be obtained for many trace elements, even when applying a purely instrumental method. Thus, the method can also be applied in the certification of reference materials, since nuclear methods are independent of chemical properties of the sample.

Activation Analysis↗
PubMed1975

[Investigations of contact tissues of Blount vitallium staples using the instrumental neutron activation analysis (author's transl)].

Instrumental neutron activation analysis with Gamma-spectroscopy is a very sensitive method for testing trace elements. Specimens of contact tissue around 5 Blount's vitallium clamps were, after preparation at the Nuclear Research Institute Jülich irradiated with thermic neutrons and their element-specific gamma spectra were measured after 33 and 125 days. In contact tissue a significant rise in concentration of the alloy-specific elements cobalt and chromium was found. The unspecific elements silver, caesium, iron, rubidium, antimon, scandium and zink were either within or very close to the normal. The metallosis of contact tissue is due to corrosion of the surfaces of cobalt-chromium implants.

Activation Analysis↗