Assignment of purity to primary metal calibrants using pin-cell VG 9000 glow discharge mass spectrometry : a primary method with direct traceability to the SI international system of units?

Download
  1. (PDF, 3 MB)
  2. Get@NRC: Assignment of purity to primary metal calibrants using pin-cell VG 9000 glow discharge mass spectrometry : a primary method with direct traceability to the SI international system of units? (Opens in a new window)
DOIResolve DOI: http://doi.org/10.1088/0026-1394/51/5/410
AuthorSearch for: ; Search for: ; Search for: ; Search for:
TypeArticle
Journal titleMetrologia
ISSN0026-1394
Volume51
Issue5
Pages410422; # of pages: 13
Subjectglow discharge mass spectrometry; primary calibrants; high-purity metals; assignment of purity; traceability; primary method; Calibrants; Glow Discharge Mass Spectrometry
AbstractA measurement model based on the use of a pin-cell glow discharge source coupled to a VG 9000 sector field mass spectrometer (GD-MS) for the assignment of purity of high-purity metals, i.e., mass fraction of metal matrix, w(M), is presented. A mass balance approach to the calculation requires the determination and summation of impurity mass fractions of all extraneous elements present, including non-metals and gases. It is posited that a primary method of measurement can be devised to yield direct traceability of results to the SI. The major source of uncertainty in the traceability chain stems from the need to adjust the initially estimated quantity values of each impurity element by a relative sensitivity factor 'influence quantity' , derived from ab initio calculations, and validated through comparison with those derived through use of Certified Reference Materials. It is argued that the method is sufficiently well understood that a measurement equation can be formulated for which all parameters are measured in terms of SI units; that all contributions to uncertainty of measurement can be quantitatively evaluated, underpinning the metrological traceability; and that the performance of GD-MS in CCQM key and pilot comparisons of trace elements in complex metal matrices is in conformance with claimed capabilities. The applicability of the approach to metals in the 3N to 7N range of purity shows that fit-for-purpose relative expanded uncertainties of 0.5% to 0.000 05% can be conservatively achieved for w(M). Presentation of various instrument calibration scenarios vis-à-vis impact on SI traceability of results is also undertaken with a view to eliciting further discussion of this concept within the metrological community.
Publication date
LanguageEnglish
AffiliationMeasurement Science and Standards; National Research Council Canada
Peer reviewedYes
NPARC number21272684
Export citationExport as RIS
Report a correctionReport a correction
Record identifier0333d7da-8a0d-4e37-a867-0cd134cebb9f
Record created2014-12-03
Record modified2016-05-09
Bookmark and share
  • Share this page with Facebook (Opens in a new window)
  • Share this page with Twitter (Opens in a new window)
  • Share this page with Google+ (Opens in a new window)
  • Share this page with Delicious (Opens in a new window)