Abstract
Results of an international intercomparison study (CCQM-P86) to assess the analytical capabilities of national metrology institutes (NMIs) and selected expert laboratories worldwide to accurately quantitate the mass fraction of selenomethionine (SeMet) and total Se in pharmaceutical tablets of selenised-yeast supplements (produced by Pharma Nord, Denmark) are presented. The study, jointly coordinated by LGC Ltd., UK, and the Institute for National Measurement Standards, National Research Council of Canada (NRCC), was conducted under the auspices of the Comité Consultatif pour la Quantité de Matière (CCQM) Inorganic Analysis Working Group and involved 15 laboratories (from 12 countries), of which ten were NMIs. Apart from a protocol for determination of moisture content and the provision of the certified reference material (CRM) SELM-1 to be used as the quality control sample, no sample preparation/extraction method was prescribed. A variety of approaches was thus used, including single-step and multiple-step enzymatic hydrolysis, enzymatic probe sonication and hydrolysis with methanesulfonic acid for SeMet, as well as microwave-assisted acid digestion and enzymatic probe sonication for total Se. For total Se, detection techniques included inductively coupled plasma (ICP) mass spectrometry (MS) with external calibration, standard additions or isotope dilution MS (IDMS), inductively coupled plasma optical emission spectrometry , flame atomic absorption spectrometry and instrumental neutron activation analysis. For determination of SeMet in the tablets, five NMIs and three academic/institute laboratories (of a total of five) relied upon measurements using IDMS. For species-specific IDMS measurements, an isotopically enriched standard of SeMet (76Se-enriched SeMet) was made available. A novel aspect of this study relies on the approach used to distinguish any errors which arise during analysis of a SeMet calibration solution from those which occur during analysis of the matrix. To help those participants undertaking SeMet analysis to do this, a blind sample in the form of a standard solution of natural abundance SeMet in 0.1 M HCl (with an expected value of 956 mg kg−1 SeMet) was provided. Both high-performance liquid chromatography (HPLC)–ICP-MS or gas chromatography (GC)–ICP-MS and GC-MS techniques were used for quantitation of SeMet. Several advances in analytical methods for determination of SeMet were identified, including the combined use of double IDMS with HPLC-ICP-MS following extraction with methanesulfonic acid and simplified two-step enzymatic hydrolysis with protease/lipase/driselase followed by HPLC-ICP-IDMS, both using a species-specific IDMS approach. Overall, satisfactory agreement amongst participants was achieved; results averaged 337.6 mg kg−1 (n = 13, with a standard deviation of 9.7 mg kg−1) and 561.5 mg kg−1(n = 11, with a standard deviation of 44.3 mg kg−1) with median values of 337.6 and 575.0 mg kg−1 for total Se and SeMet, respectively. Recovery of SeMet from SELM-1 averaged 95.0% (n = 9). The ability of NMIs and expert laboratories worldwide to deliver accurate results for total Se and SeMet in such materials (selensied-yeast tablets containing approximately 300 mg kg−1 Se) with 10% expanded uncertainty was demonstrated. The problems addressed in achieving accurate quantitation of SeMet in this product are representative of those encountered with a wide range of organometallic species in a number of common matrices.
Looking into the quantitative speciation of selenium in pharmaceutical supplements Photo courtesy of LGC.
This is a preview of subscription content, access via your institution.
References
Rayman MP (2004) Br J Nutr 92:557–573
Goenaga Infante H, Hearn R, Catterick T (2005) Anal Bioanal Chem 382:957–967
Clark LC, Combs GF, Turnbull BW, Slate EH, Chalker DK, Chow J, Davis LS, Glover RA, Graham GF, Gross EG, Krongrad A, Lesher JL, Parl K, Sanders BB, Smith CL, Taylor R (1996) J Am Med Assoc 276:1957–1963
Lobinski R, Edmonds JS, Suzuki KT, Uden PC (2000) Pure Appl Chem 72:447–461
Uden PC (2002) Anal Bioanal Chem 373:422–431
Yang L, Mester Z, Sturgeon R (2004) Anal Chem 76:5149–5156
Yang L, Sturgeon RE, McSheehy S, Mester Z (2004) J Chromatogr A 1055:177–184
Wolf WR, Zainal H, Yager B (2001) Fresenius J Anal Chem 370:286–290
Yang L, Sturgeon RE, Wolf WR, Goldschmidt RJ, Mester Z (2004) J Anal At Spectrom 19:1448–1453
Mester Z, Willie S, Yang L, Sturgeon R, Caruso JA, Fernández ML, Fodor P, Goldschmidt RJ, Goenaga-Infante H, Lobinski R, Maxwell P, McSheehy S, Polatajko A, Sadi BB, Sanz-Medel A, Scriver C, Szpunar J, Wahlen R, Wolf W (2006) Anal Bioanal Chem 385:168–180
Goenaga Infante H, O’Connor G, Rayman M, Spallholz JE, Wahlen R, Hearn R, Catterick T (2005) J Anal At Spectrom 20:864–870
Díaz Huerta V, Hinojosa Reyes L, Marchante-Gayón JM, Fernández Sánchez ML, Sanz-Medel A (2003) J Anal At Spectrom 18:1243–1247
Potalajko A, Sliwka-Kaszynska M, Dernovics M, Ruzik R, Encinar JR, Szpunar J (2004) J Anal At Spectrom 19:114–120
Encinar JR, Ouerdane L, Buchmann W, Tortajada J, Lobinski R, Szpunar J (2003) Anal Chem 75:3765–3774
Uden PC, Boakye HT, Kahakachchi C, Hafezi R, Nolibos P, Block E, Johnson S, Tyson JF (2004) J Anal At Spectrom 19:65–73
Wrobel K, Wrobel K, Caruso JA (2002) J Anal At Spectrom 17:1048–1054
McSheehy S, Kelly J, Tessier L, Mester Z (2005) Analyst 130:35–37
Larsen EH, Hansen M, Paulin H, Moesgaard S, Reid M, Rayman M (2004) J AOAC Int 87:225–232
Szpunar J (2005) Analyst 4:442–465
Dumont E, De Cremer K, Van Hulle M, Chéry CC, Vanhaecke F, Cornelis R (2004) J Anal At Spectrom 19:167–171
Capelo JL, Ximénez-Embun P, Madrid-Albarrán Y, Cámara C (2004) Anal Chem 76:233–237
Bodo ET, Stefanka Z, Ipolyi I, Soros C, Dernovics M, Fodor P (2003) Anal Bioanal Chem 377:32–38
Polatajko A, Bana B, Encinar JR, Szpunar J (2005) Anal Bioanal Chem 381:844–849
ISO (1993) Guide to the expression of uncertainty in measurement. ISO, Geneva
Heumann KG, Rottmann L, Vogl J (1994) J Anal At Spectrom 9:1351–1355
McSheehy S, Pannier F, Szpunar J, Potin-Gautier M, Lobinski R (2002) Analyst 127:223–229
Cox M (2000) In Ciarlini P, Forbes AB, Pavese F, Ritcher D (eds) Advanced mathematical and computational tools in metrology IV, World Scientific, Singapore, pp 45–65
Amoako PO, Kahakachchi CL, Dodova EN, Uden PC, Tyson JF (2007) J Anal At Spectrom 22:938–946
Acknowledgements
LGC particularly acknowledges the efforts of E. Warburton and the Reference Materials Team, especially D. Curtis for help with sending the samples and standards to the participants. Special thanks go to S. Moesgaard from Pharma Nord, Vejle, Denmark, for providing the CCQM-P86 tablets. The pilot laboratories acknowledge, in particular, the efforts of R. Harte for sending the relevant documents to the participants and for collecting the data. The work described in this paper was supported by the UK Department for Innovation, Universities & Skills as part of the National Measurement System Chemical & Biological Metrology Knowledge Base Programme.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Goenaga-Infante, H., Sturgeon, R., Turner, J. et al. Total selenium and selenomethionine in pharmaceutical yeast tablets: assessment of the state of the art of measurement capabilities through international intercomparison CCQM-P86. Anal Bioanal Chem 390, 629–642 (2008). https://doi.org/10.1007/s00216-007-1654-8
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00216-007-1654-8
Keywords
- Pilot study CCQM-P86
- Pharmaceutical tablets
- Selenised-yeast supplements
- Selenomethionine
- Total selenium
- Isotope dilution mass spectrometry