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Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement (v.7, #12)
The view of IRMM on accreditation of CRM producers by J. Pauwels; M. Grasserbauer (pp. 516-519).
This article describes the views of IRMM on accreditation of CRM producers and the philosophy which is behind these views. More specifically, it explains the reasons for choosing ISO Guide 34 rather than ISO/IEC 17025 as the basis document for the proposed accreditation of its CRM activites.
Keywords: Keywords Certified reference material; Reference material production; Certification process; Sources of uncertainty; Accreditation; ISO; REMCO
Metrological considerations in flame atomic absorption analyses versus certified reference materials of soils from Onondaga County, New York State, USA for background trace metal content by J. D. Fox; J. S. Fox (pp. 520-528).
Acid-extractable quantities of the elements silver (Ag), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) in 107 undeveloped soil samples from Onondaga County, New York, USA were determined versus two commercially available certified reference soils utilizing United States Environmental Protection Agency (USEPA) Methods 3050B and 7000B. This work focuses on metrology where the flame atomic absorption (FLAA) results for the certified reference soils indicated excess recoveries of 52, 54 and 33% by weight for the elements Cr, Ni and Pb, respectively. The excess discrepancies were not manifest in the results for the elements Ag, Cd, Cu, and Zn. The overall mean background levels in mg/kg dry weight for each metal in Onondaga County soil were Ag <12, Cd <8, Cr = 18, Cu = 19, Ni = 18, Pb <17, and Zn = 45.
Keywords: Keywords Soils; Onondaga County; Flame atomic absorption; Certified reference soils; Metrology
Traceability of measurement results of the effective acquisition time in gamma-ray spectrometry implemented by the pulser method by D. Glavič-Cindro; M. Korun; B. Vodenik (pp. 529-537).
Measurement of the effective acquisition time of a spectrum by the pulser method is described. The measurement results were verified up to count rates of 12000 s–1 at various settings of the pulse processing electronics and spectral shapes. Systematic effects of up to 2% were observed. The clocks in the spectrometers were calibrated by counting pulses generated by the DCF 77 signal with the frequency of 1 Hz. In 1-day measurements at low count rates a relative uncertainty of about 0.5 10–3 of the effective acquisition time was obtained. At counting losses up to 30% the relative uncertainty remained below 1.5 10–2.
Keywords: Keywords Gamma-ray spectrometry; Pulser method; Uncertainty; Traceability