Accurate quantification of selenoproteins in human plasma/serum by isotope dilution ICP-MS: focus on selenoprotein P

M. Estela del Castillo Busto, Caroline Oster, Susana Cuello-Nunez, Christian L. Deitrich, Andrea Raab, Anna Konopka, Wolf D. Lehmann, Heidi Goenaga-Infante, Paola Fisicaro*

*Corresponding author for this work

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Abstract

A species-specific isotope dilution analysis (SS IDA) method was developed for the first time for the determination of selenoprotein P (SEPP1) in human plasma/serum at the protein level by double affinity HPLC-ICP-MS. In this regard, a standard and a spike of SEPP1 were produced by cell-free E. coli protein synthesis, where Se (ICP tag) was introduced in the form of selenomethionine (SeMet) allowing for the absolute SEPP1 quantification by ICP-MS. A complete characterization of the standard and the spike was carried out in terms of isotopic composition and Se mass fraction by collision-cell ICP-MS to ensure SI-traceability. Method development and validation were conducted using the reference materials BCR-637, extensively analysed for its Se species, and the SRM 1950, which provides reference values for Se species (including SEPP1). Stability of the isotope ratio R77/76 in the sample blends was tested for one month with negligible change. Relative expanded uncertainties of 5.7% and 7.7% were achieved for BCR-637 and SRM 1950 for mass fractions of 55.5 and 63.9 ng g(-1) Se for SEPP1, respectively. The developed SEPP1 SS IDA methodology could be a valuable tool to establish references values for selenoproteins in clinical chemistry and showed the potential of cell-free protein synthesis for the preparation of future stable isotope-labeled intact selenoproteins.

Original languageEnglish
Pages (from-to)1904-1912
Number of pages9
JournalJournal of Analytical Atomic Spectrometry
Volume31
Issue number9
Early online date26 Jul 2016
DOIs
Publication statusPublished - 1 Sep 2016

Keywords

  • HUMAN SERUM
  • SIMULTANEOUS SPECIATION
  • QUADRUPOLE MS
  • AFFINITY HPLC
  • SELENIUM
  • ONLINE

Cite this

Busto, M. E. D. C., Oster, C., Cuello-Nunez, S., Deitrich, C. L., Raab, A., Konopka, A., Lehmann, W. D., Goenaga-Infante, H., & Fisicaro, P. (2016). Accurate quantification of selenoproteins in human plasma/serum by isotope dilution ICP-MS: focus on selenoprotein P. Journal of Analytical Atomic Spectrometry, 31(9), 1904-1912. https://doi.org/10.1039/c6ja00122j