Analytical and Bioanalytical Chemistry

, Volume 385, Issue 1, pp 168–180

Certification of a new selenized yeast reference material (SELM-1) for methionine, selenomethinone and total selenium content and its use in an intercomparison exercise for quantifying these analytes

  • Zoltán Mester
  • Scott Willie
  • Lu Yang
  • Ralph Sturgeon
  • Joseph A. Caruso
  • María Luisa Fernández
  • Peter Fodor
  • Robert J. Goldschmidt
  • Heidi Goenaga-Infante
  • Ryszard Lobinski
  • Paulette Maxwell
  • Shona McSheehy
  • Aleksandra Polatajko
  • Baki B. M. Sadi
  • Alfredo Sanz-Medel
  • Christine Scriver
  • Joanna Szpunar
  • Raimund Wahlen
  • Wayne Wolf
Original Paper

DOI: 10.1007/s00216-006-0338-0

Cite this article as:
Mester, Z., Willie, S., Yang, L. et al. Anal Bioanal Chem (2006) 385: 168. doi:10.1007/s00216-006-0338-0

Abstract

A new selenized yeast reference material (SELM-1) produced by the Institute for National Measurement Standards, National Research Council of Canada (INMS, NRC) certified for total selenium (2,059±64 mg kg−1), methionine (Met, 5,758±277 mg kg−1) and selenomethionine (SeMet, 3,431±157 mg kg−1) content is described. The ±value represents an expanded uncertainty with a coverage factor of 2. SeMet and Met amount contents were established following a methanesulfonic acid digestion of the yeast using GC-MS and LC-MS quantitation. Isotope dilution (ID) calibration was used for both compounds, using 13C-labelled SeMet and Met. Total Se was determined after complete microwave acid digestion based on ID ICP-MS using a 82Se spike or ICP-OES spectrometry using external calibration. An international intercomparison exercise was piloted by NRC to assess the state-of-the-art of measurement of selenomethione in SELM-1. Determination of total Se and methionine was also attempted. Seven laboratories submitted results (2 National Metrology Institutes (NMIs) and 5 university/government laboratories). For SeMet, ten independent mean values were generated. Various acid digestion and enzymatic procedures followed by LC ICP-MS, LC AFS or GC-MS quantitation were used. Four values were based on species-specific ID calibration, one on non-species-specific ID with the remainder using standard addition (SA) or external calibration (EC). For total selenium, laboratories employed various acid digestion procedures followed by ICP-MS, AFS or GC-MS quantitation. Four laboratories employed ID calibration, the remaining used SA or EC. A total of seven independent results were submitted. Results for methionine were reported by only three laboratories, all of which used various acid digestion protocols combined with determination by GC-MS and LC UV. The majority of participants submitted values within the certified range for SeMet and total Se, whereas the intercomparison was judged unsuccessful for Met because only two external laboratories provided values, both of which were outside the certified range.

Keywords

SelenomethionineYeastReference materialSpeciationIntercomparison

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Zoltán Mester
    • 1
  • Scott Willie
    • 1
  • Lu Yang
    • 1
  • Ralph Sturgeon
    • 1
  • Joseph A. Caruso
    • 2
  • María Luisa Fernández
    • 3
  • Peter Fodor
    • 4
  • Robert J. Goldschmidt
    • 5
  • Heidi Goenaga-Infante
    • 6
  • Ryszard Lobinski
    • 7
    • 8
  • Paulette Maxwell
    • 1
  • Shona McSheehy
    • 1
  • Aleksandra Polatajko
    • 7
    • 8
  • Baki B. M. Sadi
    • 2
  • Alfredo Sanz-Medel
    • 3
  • Christine Scriver
    • 1
  • Joanna Szpunar
    • 7
  • Raimund Wahlen
    • 6
  • Wayne Wolf
    • 5
  1. 1.Institute for National Measurement StandardsNational Research Council of CanadaOttawaCanada
  2. 2.University of CincinnatiDepartment of ChemistryCincinnatiUSA
  3. 3.Department of Physical and Analytical ChemistryUniversity of OviedoOviedoSpain
  4. 4.Department of Applied ChemistryCorvinus University of BudapestBudapestHungary
  5. 5.Food Composition LaboratoryBHNRC, ARS, USDABeltsvilleUSA
  6. 6.Laboratory of the Government ChemistTeddingtonUK
  7. 7.Group of Bio-Inorganic Analytical ChemistryCNRS UMR 5034PauFrance
  8. 8.Department of ChemistryWarsaw University of TechnologyWarsawPoland