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Impact of pump flow fluctuations on post column online ID-ICP-MS

  • Claudia SwartEmail author
  • Olaf Rienitz
  • Detlef Schiel
Technical Note

Abstract

In post column online isotope dilution mass spectrometry (IDMS), the stability of the spike mass flow is a key element. Changes in viscosity or fluctuations in the pump rate of the peristaltic pump may affect the results of post column online IDMS measurements. It was shown by simulating random fluctuations and studying the changes in the resulting integrals of the isotope ratio chromatogram of the sample that even small fluctuations, observable when using peristaltic pumps, can influence the result and especially its uncertainty. The use of a balance to continuously monitor the mass flow of the spike during the measurement which we presented in a previous publication allows now to correct the isotope ratio chromatogram for these fluctuations. Subsequently, the simulated effect was verified experimentally for the determination of Se-Met in the human serum reference material BCR 637, where the corrected mass fraction was plainly closer to the mass fraction obtained by species specific IDMS. Additional attention was paid to the fact that there is a time shift between the observation of the fluctuations in the pump rate and the detection of these fluctuations in the ICP-MS.

Figure

The success of correcting for pump flow fluctuations depends strongly on the application of the accurate time shift. Green to red: increasing deviation from the accurate time shift results in an increasing ineffectiveness of the correction applied

Keywords

Online double IDMS Mass flow fluctuations Species analysis Se-methionine Human serum 

Notes

Acknowledgements

The research within this EURAMET joint research project receives funding from the European Community’s Seventh Framework Programme, ERA-NET Plus, under Grant agreement no. 217257.

References

  1. 1.
    Sargent M, Harrington C, Harte R (eds) (2002) Guidelines for achieving high accuracy in isotope dilution mass spectrometry (IDMS). Royal Society of Chemistry, Cambridge, p 50Google Scholar
  2. 2.
    Heumann KG (1988) Isotope dilution mass spectrometry. In: Adams F, Gijbels R, van Grieken R (eds) Inorganic mass spectrometry. Wiley, New York, pp 301–376Google Scholar
  3. 3.
    Heumann KG, Rottmann L, Vogl J (1994) Elemental speciation with liquid chromatography-inductively coupled plasma isotope dilution mass spectrometry. JAAS 9:1351–1355Google Scholar
  4. 4.
    Rienitz O, Pramann A, Schiel D (2010) Novel concept for the mass spectrometric determination of absolute isotopic abundances with improved measurement uncertainty. Int J Mass Spectrom 289:47–53CrossRefGoogle Scholar
  5. 5.
    Meija J, Mester Z (2008) Paradigms in isotope dilution mass spectrometry for elemental speciation analysis. Anal Chim Acta 607(2):115–125CrossRefGoogle Scholar
  6. 6.
    Encinar JR, Schaumlöffel D, Ogra Y, Lobinski R (2004) Determination of selenomethionine and selenocysteine in human serum using speciated isotope dilution-capillary HPLC-inductively coupled plasma collision cell mass spectrometry. Anal Chem 76(22):6635–6642CrossRefGoogle Scholar
  7. 7.
    Goenaga-Infante H, Sturgeon R, Turner J, Hearn R, Sargent M, Maxwell P, Yang L, Barzev A, Pedrero Z, Cámara C, Díaz Huerta V, Fernández Sánchez M, Sanz-Medel A, Emese K, Fodor P, Wolf W, Goldschmidt R, Vacchina V, Szpunar J, Valiente L, Huertas R, Labarraque G, Davis C, Zeisler R, Turk G, Rizzio E, Mackay L, Myors R, Saxby D, Askew S, Chao W, Jun W (2008) 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(2):629–642CrossRefGoogle Scholar
  8. 8.
    Rottmann L, Heumann KG (1994) Development of an on-line isotope dilution technique with HPLC/ICP-MS for the accurate determination of elemental species. Fresenius J Anal Chem 350(4):221–227CrossRefGoogle Scholar
  9. 9.
    Heumann KG, Gallus SM, Rädlinger G, Vogl J (1998) Accurate determination of element species by on-line coupling of chromatographic systems with ICP-MS using isotope dilution technique. Spectrochim Acta Part B: At Spectrosc 53(2):273–287CrossRefGoogle Scholar
  10. 10.
    Swart C, Rienitz O, Schiel D (2011) Alternative approach to post column online isotope dilution ICP-MS. Talanta 83(5):1544–1551CrossRefGoogle Scholar
  11. 11.
    Rayman MP (2004) The use of high-selenium yeast to raise selenium status: How does it measure up? Br J Nutr 92(4):557–573CrossRefGoogle Scholar
  12. 12.
    Davis RS (1998) The fourth meeting of the CCQM, February 1998. Accred Qual Assur 3:502–503CrossRefGoogle Scholar
  13. 13.
    De Bièvre P, Peiser HS (1997) Basic equations and uncertainties in isotope-dilution mass spectrometry for traceability to SI of values obtained by this primary method. Fresenius J Anal Chem 359(7):523–525CrossRefGoogle Scholar
  14. 14.
    Deitrich C, Swart C, Rienitz O, Jitaru P, Fisicaro P, Long S, Albarran YM, Infante HG (2011) Improved extraction and isotope dilution strategies for the traceable quantification of selenomethionine at low parts per billion levels in human serum. Anal Chem (in press)Google Scholar
  15. 15.
    Berglund M, Wieser ME (2011) Isotopic compositions of the elements 2009 (IUPAC technical report). Pure Appl Chem 83(2):397–410CrossRefGoogle Scholar
  16. 16.
    Evaluation of measurement data—Guide to the expression of uncertainty in measurement JCGM 100:2008Google Scholar

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  1. 1.Physikalisch-Technische BundesanstaltBraunschweigGermany

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