Revisiting type-A uncertainties relating to the measurement of mass fraction of lead using isotope-dilution inductively coupled plasma mass spectrometry: A way of improving measurement precision and expanded uncertainty

Chung Wah James LAM, Yiu Chung YIP, Wai Fong TONG

Research output: Contribution to journalArticles

4 Citations (Scopus)

Abstract

A quadrupole inductively coupled plasma mass spectrometer (Q-ICP-MS) has been used for determination of lead in plant materials using isotope-dilution inductively coupled plasma mass spectrometry. The accuracy of the method was demonstrated by analysis of a matrix certified reference material, NIST SRM 1547 Peach Leaves. Specific instrumental parameters of Q-ICP-MS, including isotope analysis mode, integration time per point, number of points per mass, and number of measurements, were optimized to obtain the best measurement precision. The precision (expressed as relative standard deviation) associated with replicate measurement of the ²⁰⁸Pb/²⁰⁶Pb isotope ratio and its mass-bias correction factor was <0.2%. Following “Example A7” of the Eurachem/CITAC Guide, the relative expanded uncertainty, U rel, (coverage factor k = 2) was found to be ±1.1%, which fulfilled the target value of ±2% maximum and was lower than the uncertainty of ±3.4% reported by NIST based on isotope-dilution thermal ionization mass spectrometry. Sample recovery of 99% was obtained. Copyright © 2008 Springer-Verlag.
Original languageEnglish
Pages (from-to)311-319
JournalAccreditation and Quality Assurance
Volume13
Issue number6
DOIs
Publication statusPublished - Jun 2008

Citation

Lam, J. C. W., Yip, Y., & Tong, W. (2008). Revisiting type-A uncertainties relating to the measurement of mass fraction of lead using isotope-dilution inductively coupled plasma mass spectrometry: A way of improving measurement precision and expanded uncertainty. Accreditation and Quality Assurance, 13(6), 311-319. doi: 10.1007/s00769-008-0384-8

Keywords

  • Q-ICP-MS
  • ID-ICP-MS
  • Precision
  • Lead isotope ratios
  • Uncertainty

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