Journal of Radioanalytical and Nuclear Chemistry

, Volume 296, Issue 3, pp 1295–1302 | Cite as

Effect of nitrate on the determination of iron concentration in phytoplankton culture medium by liquid scintillation counting (LSC) method using 55Fe as radioisotope tracer

  • Chikako Okumura
  • M. Azizur Rahman
  • Akira Takimoto
  • Hiroshi Hasegawa


Liquid scintillation counting (LSC) method using a radioisotope tracer has several advantages such as simple procedure, high sensitivity and low detection limit, and has been used for the determination Fe concentrations in water samples. Several factors such as nitrate concentration, pH, chelating ligand affect the efficiency of this method in the determination of iron (Fe) in waters. In this study, the effect of nitrate in phytoplankton culture medium on the determination of Fe concentration by LSC method using 55Fe radioisotope tracer was evaluated. The measured Fe concentrations in the medium were lower than its added concentration (1.5 μM) when liquid samples contain nitrate. Fe concentrations decreased exponentially as nitrate concentrations increased up to 2.64 mM, reaching a constant value of 1.31 μM Fe at nitrate concentrations higher than 2.64 mM. A correction factor (f = 1.14) was calculated from the decrease rate of Fe concentrations at different nitrate concentrations in the phytoplankton culture medium. This correction factor can be used to correct the measurement values of Fe concentrations in phytoplankton culture medium obtained from LSC method. Our results showed that up to 94 % of the added Fe can be determined by LSC using 55Fe radioisotope tracer. The remaining 6 % was probably bound to the walls of the culturing vessel. This method is also applicable for the measurement of Fe size-fractionation in phytoplankton culture medium.


Iron Phytoplankton culture medium Iron Fractionation Liquid scintillation counting (LSC) method 



This research was partly supported by a Grant-in-Aid for Scientific Research (18510071) from Japan Society for the Promotion of Science (JSPS) and the Steel Industry Foundation for the Advancement of Environmental Protection Technology, Japan. The authors also wish to thank the University of Technology, Sydney (UTS), Australia, for supporting the research. We also would like to thank Dr. Anne Colville, School of Environmental Sciences, University of Technology Sydney (UTS), Australia, for reviewing the manuscript and making a number of helpful suggestions prior to submission.


  1. 1.
    Geider R, Roche J (1994) Photosynth Res 39:275–301CrossRefGoogle Scholar
  2. 2.
    Sunda WG, Swift DG, Huntsman SA (1991) Nature 351:55–57CrossRefGoogle Scholar
  3. 3.
    Sunda WG, Huntsman SA (1997) Nature 390:389–392CrossRefGoogle Scholar
  4. 4.
    Maldonado MT, Price NM (2000) Limnol Oceanogr 45(4):814–826CrossRefGoogle Scholar
  5. 5.
    Taylor SR (1964) Geochim Cosmochim Acta 28:1273–1285CrossRefGoogle Scholar
  6. 6.
    Morel FMM, Hering JG (1993) Principles and applications of aquatic chemistry. Wiley-Interscience, New YorkGoogle Scholar
  7. 7.
    Kuma K, Nishioka J, Matsunaga K (1996) Limnol Oceanogr 41:396–407CrossRefGoogle Scholar
  8. 8.
    Liu X, Millero FJ (2002) Mar Chem 77:43–54CrossRefGoogle Scholar
  9. 9.
    Johnson KS, Gordon RM, Coale KH (1997) Mar Chem 57:137–161CrossRefGoogle Scholar
  10. 10.
    Lewin J, Chen C (1973) Limnol Oceanogr 18:590–596CrossRefGoogle Scholar
  11. 11.
    Nishioka J, Takeda S (2000) Mar Biol 137:231–238CrossRefGoogle Scholar
  12. 12.
    Kuma K, Katsumoto A, Shiga N, Sawabe T, Matsunaga K (2000) Mar Chem 71:111–123CrossRefGoogle Scholar
  13. 13.
    King JN, Fritz JS (1985) Anal Chem 57:1016–1020CrossRefGoogle Scholar
  14. 14.
    Van Geen A, Boyle E (1990) Anal Chem 62:1705–1709CrossRefGoogle Scholar
  15. 15.
    Sohrin Y, Iwamoto S-i, Akiyama S, Fujita T, Kugii T, Obata H, Nakayama E, Goda S, Fujishima Y, Hasegawa H, Ueda K, Matsui M (1998) Anal Chim Acta 363:11–19CrossRefGoogle Scholar
  16. 16.
    Wells ML, Bruland KW (1998) Mar Chem 63:145–153CrossRefGoogle Scholar
  17. 17.
    Gobler CJ, Donat JR, Consolvo JA III, Sañudo-Wilhelmy SA (2002) Mar Chem 77:71–89CrossRefGoogle Scholar
  18. 18.
    Akatsuka K, McLaren JW, Lam JW, Berman SS (1992) J Anal At Spectrom 7:889–894CrossRefGoogle Scholar
  19. 19.
    van den Berg CMG (1995) Mar Chem 50:139–157CrossRefGoogle Scholar
  20. 20.
    Wu J, Luther GW (1995) Mar Chem 50:159–177CrossRefGoogle Scholar
  21. 21.
    Rue EL, Bruland KW (1997) Limnol Oceanogr 42:901–910CrossRefGoogle Scholar
  22. 22.
    Bruland KW, Rue EL, Smith GJ (2001) Limnol Oceanogr 46:1661–1674CrossRefGoogle Scholar
  23. 23.
    Hudson RJM, Morel FMM (1989) Limnol Oceanogr 34:1113–1120CrossRefGoogle Scholar
  24. 24.
    Hudson RJM, Morel FMM (1990) Limnol Oceanogr 35:1002–1020CrossRefGoogle Scholar
  25. 25.
    Shaked Y, Kustka AB, Morel FMM, Erel Y (2004) Limnol Oceanogr Methods 2:137–145CrossRefGoogle Scholar
  26. 26.
    Grahek Ž, Rožmarić MM (2005) J Radioanal Nucl Chem 267:131–137CrossRefGoogle Scholar
  27. 27.
    Lyman J, Fleming RH (1940) J Mar Res 3:134–146Google Scholar
  28. 28.
    Watanabe MM, Kawachi M, Hiroki M, Kasai F (2000) NIES collection list of strains: microalgae and protozoa. National Institute for Environmental Studies, Tsukuba, p 159Google Scholar
  29. 29.
    Malonda AG (1999) Free parameter models in liquid scintillation counting. CIEMAT, Madrid, p 416Google Scholar
  30. 30.
    Kuma K, Nakabayashi S, Suzuki Y, Matsunaga K (1992) Mar Chem 38:133–143CrossRefGoogle Scholar

Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2012

Authors and Affiliations

  • Chikako Okumura
    • 1
  • M. Azizur Rahman
    • 1
    • 2
  • Akira Takimoto
    • 4
  • Hiroshi Hasegawa
    • 3
  1. 1.Graduate School of Natural Science and TechnologyKanazawa UniversityKakuma, KanazawaJapan
  2. 2.Centre for Environmental Sustainability, School of the EnvironmentUniversity of TechnologySydneyAustralia
  3. 3.Institute of Science and EngineeringKanazawa UniversityKakuma, KanazawaJapan
  4. 4.Institute of Science and Engineering, Faculty of Mechanical EngineeringKanazawa UniversityKakuma, KanazawaJapan

Personalised recommendations