scholarly journals Quantifying Heterogeneity of Small Test Portion Masses of Geological Reference Materials by Portable XRF Spectrometry: Implications for Uncertainty of Reference Values

2017 ◽  
Vol 41 (3) ◽  
pp. 459-473 ◽  
Author(s):  
Peter D. Rostron ◽  
Michael H. Ramsey
Keyword(s):  
Reference Materials ◽  
Reference Values ◽  
Portable Xrf ◽  
Test Portion ◽  
Small Test

scholarly journals Erratum: Revised δ 34 S reference values for IAEA sulfur isotope reference materials S-2 and S-3

2009 ◽  
Vol 23 (11) ◽  
pp. 1746-1746
Author(s):  
Jacqueline L. Mann ◽  
Robert D. Vocke ◽  
W. Robert Kelly
Keyword(s):  
Reference Materials ◽  
Reference Values ◽  
Sulfur Isotope

Revised δ 34 S reference values for IAEA sulfur isotope reference materials S-2 and S-3

2009 ◽  
Vol 23 (8) ◽  
pp. 1116-1124 ◽  
Author(s):  
Jacqueline L. Mann ◽  
Robert D. Vocke ◽  
W. Robert Kelly
Keyword(s):  
Reference Materials ◽  
Reference Values ◽  
Sulfur Isotope

Reference Values Following ISO Guidelines for Frequently Requested Rock Reference Materials

2016 ◽  
Vol 40 (3) ◽  
pp. 333-350 ◽  
Author(s):  
Klaus Peter Jochum ◽  
Ulrike Weis ◽  
Beate Schwager ◽  
Brigitte Stoll ◽  
Stephen A. Wilson ◽  
...  
Keyword(s):  
Reference Materials ◽  
Reference Values

scholarly journals Comparison of Closed-Vessel and Focused Open-Vessel Microwave Dissolution for Determination of Cadmium, Copper, Lead, and Selenium in Wheat, Wheat Products, Corn Bran, and Rice Flour by Transverse-Heated Graphite Furnace Atomic Absorption Spectrometry

1997 ◽  
Vol 80 (2) ◽  
pp. 379-387 ◽  
Author(s):  
Eugene J Gawalko ◽  
Thomas W Nowicki ◽  
Jeff Babb ◽  
Russell Tkachuk ◽  
Shaole Wu
Keyword(s):  
Nitric Acid ◽  
Atomic Absorption ◽  
Reference Materials ◽  
Reference Values ◽  
Certified Reference Materials ◽  
Graphite Furnace ◽  
Microwave Digestion ◽  
Research Centre ◽  
Closed Vessel

Abstract A method is described for the determination of Pb, Cd, Cu, and Se in cereal samples. An atomic absorption spectrometer equipped with a transverseheated graphite furnace with Zeeman background correction was used for all determinations. Sample preparation was performed by closed-vessel microwave digestion using nitric acid and focused openvessel microwave digestion using nitric acid-hydrogen peroxide. Both techniques were evaluated by using 15 cereal reference materials and comparing results with certified or reference values for each element. Cereal reference standards obtained from the Community Bureau of Reference (Europe), the National Institute of Standards and Technology (USA), the National Institute for Environmental Studies (Japan), the National Research Centre for Certified Reference Materials (People's Republic of China), and the Canadian Grain Commission were used. Application of a series of t-tests, conducted according to Sidak's modified Bonerroni t-procedure, showed that both techniques yielded accurate results for cereal reference materials. Some differences from certified and reference values, however, were found for each element.

Layered and ion implantation specimens as possible reference materials for the electron-probe microanalysis

1992 ◽  
Vol 50 (2) ◽  
pp. 1652-1653
Author(s):  
G. Remond ◽  
R.H. Packwood ◽  
C. Gilles ◽  
S. Chryssoulis
Keyword(s):  
Ion Implantation ◽  
Reference Materials ◽  
Analytical Techniques ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
X Ray ◽  
Spatially Resolved ◽  
Analytical Expressions ◽  
Original Approach ◽  
Depth Concentration

Merits and limitations of layered and ion implanted specimens as possible reference materials to calibrate spatially resolved analytical techniques are discussed and illustrated for the case of gold analysis in minerals by means of x-ray spectrometry with the EPMA. To overcome the random heterogeneities of minerals, thin film deposition and ion implantation may offer an original approach to the manufacture of controlled concentration/ distribution reference materials for quantification of trace elements with the same matrix as the unknown.In order to evaluate the accuracy of data obtained by EPMA we have compared measured and calculated x-ray intensities for homogeneous and heterogeneous specimens. Au Lα and Au Mα x-ray intensities were recorded at various electron beam energies, and hence at various sampling depths, for gold coated and gold implanted specimens. X-ray intensity calculations are based on the use of analytical expressions for both the depth ionization Φ (ρz) and the depth concentration C (ρz) distributions respectively.

EURRECA’s Approach for Estimating Micronutrient Requirements

2011 ◽  
Vol 81 (4) ◽  
pp. 256-263 ◽  
Author(s):  
Christophe Matthys ◽  
Pieter van ‘t Veer ◽  
Lisette de Groot ◽  
Lee Hooper ◽  
Adriënne E.J.M. Cavelaars ◽  
...  
Keyword(s):  
Reference Values ◽  
Policy Decision ◽  
Individual Variability ◽  
The Body ◽  
Decision Makers ◽  
Nutrient Requirements ◽  
Factorial Approach ◽  
Dietary Reference Values ◽  
Health Policy Decision ◽  
Quantitative Integration

In Europe, micronutrient dietary reference values have been established by (inter)national committees of experts and are used by public health policy decision-makers to monitor and assess the adequacy of diets within population groups. The approaches used to derive dietary reference values (including average requirements) vary considerably across countries, and so far no evidence-based reason has been identified for this variation. Nutrient requirements are traditionally based on the minimum amount of a nutrient needed by an individual to avoid deficiency, and is defined by the body’s physiological needs. Alternatively the requirement can be defined as the intake at which health is optimal, including the prevention of chronic diet-related diseases. Both approaches are confronted with many challenges (e. g., bioavailability, inter and intra-individual variability). EURRECA has derived a transparent approach for the quantitative integration of evidence on Intake-Status-Health associations and/or Factorial approach (including bioavailability) estimates. To facilitate the derivation of dietary reference values, EURopean micronutrient RECommendations Aligned (EURRECA) is developing a process flow chart to guide nutrient requirement-setting bodies through the process of setting dietary reference values, which aims to facilitate the scientific alignment of deriving these values.

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