1,721,015 research outputs found
Analisi per attivazione neutronica presso l'I.N.Ri.M.: Utilizzo e certificazione di materiali di riferimento
No full textL’analisi per attivazione neutronica come metodo primario nella determinazione di elementi in tracce in campioni di origine biologica
No full textMetrological traceability in chemistry: examples of applications of INAA in food analysis in: Round table on Traceability in chemistry, health, food and nutrition
No full textA feasibility study for the measurement of the 30Si mole fraction of the AVO28 material by Instrumental Neutron Activation Analysis
No full textThe possibility of using neutron activation to experimentally determine the 30Si mole fraction of the ultra-pure silicon AVO28 material highly enriched in 28Si that being used for the determination of the Avogadro constant has been investigated. Specifically, a 6 g sample of a natural silicon material (WASO04) was irradiated and measured to model the expected signal that would be produced in a sample of the AVO28 material of similar mass and subjected to the same experimental conditions. Data from this experiment has been used to evaluate the contributions which are expected to dominate the measurement uncertainty. The measurement of the 30Si mole fraction of the AVO28 material by neutron activation appears to be feasible and the provisional relative uncertainty is evaluated to be about 3%
Instrumental neutron activation analysis of an enriched 28Si single-crystal
No full textThe determination of the Avogadro constant plays a key role in the redefinition of the kilogram in terms of a fundamental constant. The present experiment makes use of a silicon single-crystal highly enriched in 28Si that must have a total impurity mass fraction smaller than a few parts in 109. To verify this requirement, we previously developed a relative analytical method based on neutron activation for the elemental characterization of a sample of the precursor natural silicon crystal WASO 04. The method is now extended to fifty-nine elements and applied to a monoisotopic 28Si single-crystal that was grown to test the achievable enrichment. Since this crystal was likely contaminated, this measurement tested also the detection capabilities of the analysis. The results quantified contaminations by Ge, Ga, As, Tm, Lu, Ta, W and Ir and, for a number of the detectable elements, demonstrated that we can already reach the targeted 1 ng/g detection limit
Controllo di qualità nell’analisi degli elementi in traccia contenuti nel particolato atmosferico
No full textAnalisi per Attivazione Neutronica di elementi in tracce nella Substantia Nigra di tessuti cerebrali umani durante l’invecchiamento.
No full textThe use of neutron activation analysis for particle size fractionation and chemical characterization of trace elements in urban air particulate matter
No full textThe concentration of more than 25 trace elements have been determined in total air particulate matter and in the size segregated fractions from the urban area of Pavia (North Italy). The PM10 fraction was also collected and analyzed. A study of the solubility in water and in physiological solution of the trace elements contained in the PM10 was also carried out. The resulting solutions were further submitted to column chromatography using Chelex 100 to perform a preliminary chemical characterization. INAA was used as the main analytical technique. ET-AAS was used for all Ph and Cd measurements and, in some cases, for the analysis of V, Mn, Cu and Ni
L’analisi per attivazione neutronica come metodo primario nella certificazione di materiali di riferimento: determinazione dell’arsenico in campioni ambientali proposti dal BIPM
No full textCaratterizzazione elementare del particolato atmosferico Himalayano (5050 s.l.m.) mediante tecniche radioanalitiche e spettrofotometriche
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