Search Results
Abstract
Twenty-four elements in six food spices were estimated by non-destructive instrumental neutron activation analysis. The problems in determining Cu were discussed.
Abstract
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.
Summary
The expression of measurement uncertainties in a standardized form is a requirement for result reliability as it imposes implications to the interpretation of analytical results. In this work, sample mass, elemental standard mass, element decay constant and sample and elemental standard activities were identified as the most important uncertainty sources for the relative method of instrumental neutron activation analysis. The contribution of these sources to the expanded standard uncertainty in the concentration of As, Co, Cr, Fe, K, Na, Se and Zn in biological materials of marine origin was assessed and sample activity was identified as the major contribution.
Abstract
Instrumental neutron activation analysis (INAA) was applied to assess element concentrations in eleven samples of mineral supplements/multivitamins acquired in drugstores and pharmacies in São Paulo city, SP, Brazil. Concentrations of Ca, Co, Cr, Cu, Fe, K, Na, Se and Zn were determined. A comparison was made between the results obtained with the labels of the mineral supplents. Certified reference materials, NIST SRM1400 Bone Ash and NIST SRM 1633b Coal Fly Ash were analyzed for quality control of the analytical results.
Abstract
A reactor-detector combination has been calibrated for routine determination of trace elements by instrumental neutron activation analysis using the semi-absolute method with flux corrections. The reproducibility of the calibration constants is studied using the standard rock AGV-1 for the activities140La,141Ce,153Sm,160Tb,152Eu,175Yb,177Lu,131Ba,60Co,51Cr,134Cs,181Hf,233Pa,46Sc, and182Ta. The results show that a calibration reproducibility with a relative precision of better than 5% can be achieved in many of the cases without any special precautions. To study the applicability of the calibration constants, concentrations of the corresponding elements have been determined in standard rocks, G-2, W-1 and GSP-1 and are compared with the recommended values.
Trace element analyses of spectroscopically pure silicon dioxide by instrumental neutron activation analysis
Implications for the analysis of geologic materials
Abstract
Spectroscopically pure, 99.999% silicon dioxide (SiO2) from five different companies was analysed for trace element impurities by instrumental neutron activation analysis using semiconductor detectors and gamma-ray spectrometry. If large amounts of these purified SiO2 samples are added to, geological samples with low trace element contents e.g., mineral separates such as quartz, feldspar and olivine, the trace element contents of the SiO2 are a significant contaminant.
Abstract
Elemental abundances determined by neutron activation usually result from comparisons of gamma-ray intensities in samples (unknown concentrations) and standards (known concentrations). If the samples and standards have large differences in gamma-ray intensity significant errors arise from coincidence losses resulting from pulse pile-up. The resolving times (the Wyttenbach factor of 2
/
) of four semiconductor germanium detectors coupled to three different multichannel analyzers used for routine activation analysis are determined with and without pile-up rejector. The errors caused by pulse pile-up in trace element abundance determination of different geological samples are tabulated.
Summary
Instrumental neutron activation analysis (INAA) was applied to determine the inorganic composition of leaves and extracts from three different species of Casearia genus plant (C. sylvestris, C. decandra and C. obliqua). Statistical analysis of the analytical data of leaf showed that the three Casearia species present similar elemental composition. Extract from C. sylvestris showed significantly different inorganic content in comparison with the two other species. Certified reference material NIST SRM-1515 Apple Leaves was analyzed for quality control.
Abstract
Several recent intercomparisons and certification exercises have shown that the determination of tin in e.g. food samples and plastics is not straightforward. k 0-Instrumental Neutron Activation Analysis (k 0-INAA) offers some intrinsic quality control opportunities for the determination of the tin content in samples since several monitoring radioisotopes are formed. In this work we will discuss the validation of the determination of tin by k 0-INAA using different reference materials. The results show that only few of these radioisotopes are reliable in terms of accuracy and that from a survey of the tin content in a range of canned foods detection limits as low as 2 mg/kg can be achieved.
Abstract
Medicinal herbs are often used as alternative medicines for healing and controlling some diseases in the world. This study focuses on the content of heavy and trace elements of some widely consumed herbs in Libya. Nine most popular herbs were analyzed by k 0-instrumental neutron activation analysis. All the samples, SRM and flux monitors were irradiated for 7 and 10 hours under thermal neutron flux of 1.3·1013 cm−2·s−1 at Tajoura nuclear reactor. In total, 33 elements were analyzed in different herbs. The variations in the concentration of the elements are attributed to soil composition and the climate in which the plant grows. The study showed that the toxic elements found in the samples were below the levels prescribed by health regulations. The precision and the accuracy of the results were evaluated by analyzing the reference materials Pine Needles SRM 1575 and Citrus Leaves SRM1572.
