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1.
The US National Institute of Standards and Technology (NIST) participated in an international interlaboratory study under
the auspices of the Consultative Committee for Amount of Substance (CCQM) for the determination of 19-norandrosterone (19-NA)
in urine, the principal metabolite of nandrolone and certain other synthetic testosterone substitutes banned for use by the
World Antidoping Agency (WADA). Prior to this study, NIST developed a candidate reference measurement procedure based upon
isotope dilution liquid chromatography/tandem mass spectrometry. This method was applied to a urine sample distributed to
the participants in the study by the Australian National Measurement Institute, Pymble, Australia (NMIA). The NIST results
were in very good agreement with those from the other participants, all of whom used methods based upon gas chromatography/mass
spectrometry. All known significant sources of uncertainty were evaluated, resulting in a relative expanded uncertainty of
less than 5% (coverage factor k = 2). 相似文献
2.
Kyung Joong Kim 《Surface and interface analysis : SIA》2022,54(4):405-416
Mutual calibration was suggested as a method to determine the absolute thickness of ultrathin oxide films. It was motivated from the large offset values in the reported thicknesses in the Consultative Committee for Amount of Substance (CCQM) pilot study P-38 for the thickness measurement of SiO2 films on Si(100) and Si(111) substrates in 2004. Large offset values from 0.5 to 1.0 nm were reported in the thicknesses by ellipsometry, X-ray reflectometry (XRR), medium-energy ion scattering spectrometry (MEIS), Rutherford backscattering spectroscopy (RBS), nuclear reaction analysis (NRA), and transmission electron microscopy (TEM). However, the offset value for the thicknesses by X-ray photoelectron spectroscopy (XPS) was close to zero (−0.013 nm). From these results, the mutual calibration method was reported for the thickness measurement of SiO2 films on Si(100) by combination of TEM and XPS. The mutual calibration method has been applied for the thickness measurements of hetero oxide films such as Al2O3 and HfO2. Recently, the effect of surface contamination was reported to be critical to the thickness measurement of HfO2 films by XPS. On the other hand, MEIS was proved to be a powerful zero offset method which is not affected by the surface contamination. As a result, the reference thicknesses in the CCQM pilot study P-190 for the thickness measurement of HfO2 films on Si(100) substrate were determined by mutual calibration method from the average XRR data and MEIS analysis. Conclusively, the thicknesses of ultrathin oxide films can be traceably certified by mutual calibration method and most thickness measurement methods can be calibrated from the certified thicknesses. 相似文献
3.
The capabilities of National Metrology Institutes (NMIs) and selected outside “expert” laboratories of determining the mass
fractions of the main and minor elements Cu, Pb, Sn, Fe, and Ni in a lead-containing brass were assessed. This pilot study
P76 was organized as an activity of the Inorganic Analysis Working Group of CCQM and was piloted by the Federal Institute
for Materials Research and Testing (BAM). In total 12 laboratories (four NMIs and eight outside labs) submitted results, some
of them more than one set of results per element. The laboratories were free to choose any analytical method they wanted to
use for the analysis. Consequently various methods of measurement were employed: inductively coupled plasma optical emission
spectrometry (ICP–OES), inductively coupled plasma mass spectrometry (ICP–MS), instrumental neutron-activation analysis (INAA),
titrimetry, flame atomic-absorption spectrometry (FAAS), spectrophotometry (MAS), electrogravimetry, and gravimetric analysis.
After testing for homogeneity within BAM, a certified reference material of lead-containing brass was used as test sample
without informing the participants about the source of the material. The agreement of the results for all elements investigated
was acceptable and mean values calculated from the results of all participants were close to the certified mass fractions
of the CRM used as test sample. No statistically significant differences between the results of the NMIs and those of the
non-NMIs could be observed. 相似文献
4.
5.
Quality of chemical measurement is a central issue nowadays with social, political and economic implications. This paper aims
to describe how interlaboratory comparisons (ILCs) can contribute towards better quality of chemical measurements. The importance
of ILCs as well as the different types and the requirements for proper organization of ILCs are explained. The international
structure and organization of metrology is given, highlighting the activities related to chemical measurements. Particularly
the use of ILCs in the service of metrology in chemistry is highlighted. A very important discussion concerning ILCs is how
they can (or cannot) establish traceability. The view of the authors is that traceability cannot, as such, be established
through ILCs. On the other hand, participation in ILCs can clearly support the claims for quality measurements, as ILCs are
experimental and objective demonstrations of measurement capability. 相似文献
6.
7.
R. I. Wielgosz 《Accreditation and quality assurance》2001,6(4-5):213-214
A report is given of the sixth meeting of the Consultative Committee on Amount of Substance (CCQM). The CCQM has been active
since 1993. It is the committee, established by the Comite International des Poids et Mesures, which is responsible for issues
regarding metrology in chemistry. It has four established working groups in the fields of organic analysis, inorganic analysis,
gas analysis and electrochemical analysis. A further twoad hoc working groups in the fields of surface analysis and metrology
in biotechnology were established during the meeting. The working groups are involved in the identification, development and
execution of a series of key comparisons, which will establish the technical basis for the mutual recognition of measurement
capabilities among the National Measurement Institutes. 17 key comparisons are currently planned for the period 1999–2002,
with 29 other international comparisons planned for the same period. 相似文献
8.
Y. C. Wong D. W. M. Sin Y. C. Yip L. Valiente A. Toervenyi J. Wang G. Labarraque P. Gupta D. Soni Surmadi E. Hwang C. Yafa O. Cankur E. Uysal G. Turk R. Huertas 《Accreditation and quality assurance》2009,14(3):151-158
A Comité Consultatif pour la Quantité de Matière (CCQM) inter-laboratory comparison program, CCQM-P97, for the analysis of
cadmium and lead in Herba Demodii Styracifolii was organized by the Hong Kong Government Laboratory. The objective of the program was to establish comparability of trace
metals analysis in herbal matrices amongst the participating national metrology institutes. The arithmetic mean values of
the 13 participants were 0.3186 mg kg−1 (RSD = 11.3%) and 1.650 mg kg−1 (RSD = 11.0%) for cadmium and lead, respectively. The participants using double-isotope dilution mass spectrometry technique
for their quantification were found to provide similar mean values to those of non-isotope dilution mass spectrometry users.
The observation indicated that trace metal analysis in herbal matrices was not method-dependent, but the use of the highest
metrological IDMS approach gave a better precision than other routine calibration methods. 相似文献
9.
Ed W. B. de Leer 《Accreditation and quality assurance》2006,11(4):175-181
This presentation to the Metrology in Chemistry symposium held in October 2004 in Beijing, describes the metrological infrastructure for gas analysis. The inputs from National Metrology Institutes, industry, standardisation and accreditation bodies, and organisers of proficiency testing schemes are briefly described.
Electronic Supplementary Material Supplementary material is available for this article at
Presented at the International Symposium on Metrology in Chemistry, 2004 Beijing, China. 相似文献
10.