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RESEARCH ARTICLE
Contents Vol 7(2)

Validation of a portable flow injection–chemiluminescence (FI-CL) method for the determination of dissolved iron in Atlantic open ocean and shelf waters by comparison with isotope dilution–inductively coupled plasma mass spectrometry (ID-ICPMS)

Simon J. Ussher A C , Ivan Petrov B , Christophe R. Quétel B and Paul J. Worsfold A
+ Author Affiliations
- Author Affiliations

A School of Geography, Earth and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth, PL4 8AA, UK.

B Institute for Reference Materials and Measurements, Joint Research Centre–European Commission, 111 Retieseweg, B-2440 Geel, Belgium.

C Corresponding author. Present address: Bermuda Institute of Ocean Sciences, 17 Biological Station, Ferry Reach, St. George’s, GE 01, Bermuda. Email: simon.ussher@bios.edu

Environmental Chemistry 7(2) 139-145 https://doi.org/10.1071/EN09092
Submitted: 16 July 2009  Accepted: 18 January 2010   Published: 22 April 2010

Environmental context. The importance of iron as a limiting micronutrient for primary production in the marine environment and its complex marine biogeochemical cycle necessitate accurate methods for the determination of iron in seawater. Current analytical challenges include the detection of trace concentrations (sub-nanomolar) and the high potential for contamination and matrix interferences. To improve confidence in dissolved iron data, intercomparison exercises of commonly used analytical methods are required that demonstrate their applicability to different water masses.

Abstract. A blind intercomparison exercise was carried out to validate a well documented, portable flow injection–chemiluminescence (FI-CL) method for the determination of iron in seawater. This was done by the analysis of a variety of filtered Atlantic Ocean samples using FI-CL and a potential primary method of measurement, isotope dilution–inductively coupled plasma mass spectrometry (ID-ICPMS). To investigate the effect of the seawater matrix at various concentrations of iron, samples were collected at various depths (0–200 m) from different water masses (European Continental Shelf, the South Atlantic Ocean) and filtered through both 0.02- and 0.2-μm pore size filters. The exercise was conducted under controlled conditions using the same bottles transported between laboratories to avoid between-bottle inhomogeneity. The results generally showed good agreement between the two methods for dissolved iron over the concentration range 0.15 to 2.1 nM. However, some samples were not in agreement according to estimated uncertainties and this was attributed to random errors arising from contamination during sample handling and matrix effects (i.e. variable interferences) rather than systematic errors.

Additional keywords: Atlantic seawater, biogeochemistry, intercomparison exercise.


Acknowledgements

S. J. Ussher and P. J. Worsfold acknowledge the Natural Environment Research Council for funding the analytical work through research grant NER/A/S/2003/00489, the European Commission for supporting time to complete the manuscript under an Marie Curie IOF ‘SOLAIROS’ project (PIOF-GA-2009-235418) and the EU COST Action (COST Action Number: ES0801) for funding a visit to the IRMM laboratory in Belgium. I. Petrov is grateful to the European Union for financial support in the form of a Ph.D. fellowship (contribution n°18858). We thank both reviewers for their constructive criticism which has contributed to the quality of this manuscript.


References


[1]   Bowie A. R., Lohan M. C., Determination of iron in seawater, in Practical Guidelines for the Analysis of Seawater (Ed. O. Wurl) 2009, Ch. 12, pp. 235–258 (CRC Press: Boca Raton, FL).

[2]   Bruland K. W., Rue E. L., Analytical methods for the determination of concentrations and speciation of iron, in The Biogeochemistry of Iron in Seawater (Eds K. A. Hunter, D. R. Turner) 2001, Ch. 6, pp. 255–289 (Wiley: New York).

[3]   K. W. Bruland , R. P. Franks , G. A. Knauer , J. H. Martin , Sampling and analytical methods for the determination of copper, cadmium, zinc, and nickel at the nanogram per liter level in sea-water. Anal. Chim. Acta 1979 , 105,  233.
        | Crossref | GoogleScholarGoogle Scholar |  open url image1

[4]   J. H. Martin , S. E. Fitzwater , Iron-deficiency limits phytoplankton growth in the northeast Pacific subarctic. Nature 1988 , 331,  341.
        | Crossref | GoogleScholarGoogle Scholar |  open url image1

[5]   M. M. Mills , C. Ridame , M. Davey , J. La Roche , R. J. Geider , Iron and phosphorus co-limit nitrogen fixation in the eastern tropical North Atlantic. Nature 2004 , 429,  292.
        | Crossref | GoogleScholarGoogle Scholar | PubMed |  open url image1

[6]   de Baar H. J. W., de Jong J. T. M., Distributions, sources and sinks of iron in seawater, in The Biogeochemistry of Iron in Seawater (Eds K. A. Hunter, D. R. Turner) 2001, Ch. 5, pp. 123–253 (Wiley: New York).

[7]   International Standards Organization, Guide to Expression of Uncertainty in Measurement 1995 (International Standards Organization: Geneva, Switzerland).

[8]   International Standards Organization, International Standard ISO/IEC 17025:2005 2005 (International Standards Organization: Geneva, Switzerland).

[9]   W. M. Landing , G. A. Cutter , J. A. Dalziel , A. R. Flegal , R. T. Powell , D. Schmidt , A. Shiller , P. Statham , et al. Analytical intercomparison results from the 1990 Intergovernmental Oceanographic-Commission open-ocean baseline survey for trace-metals: Atlantic Ocean. Mar. Chem. 1995 , 49,  253.
        | Crossref | GoogleScholarGoogle Scholar |  open url image1

[10]   J. M. Bewers , J. Dalziel , P. A. Yeats , J. L. Barron , An intercalibration for trace-metals in seawater. Mar. Chem. 1981 , 10,  173.
        | Crossref | GoogleScholarGoogle Scholar |  open url image1

[11]   C. I. Measures , S. Vink , Dissolved Fe in the upper waters of the Pacific sector of the Southern Ocean. Deep Sea Res. Part II Top. Stud. Oceanogr. 2001 , 48,  3913.
        | Crossref | GoogleScholarGoogle Scholar |  open url image1

[12]   A. R. Bowie , E. P. Achterberg , S. Blain , M. Boye , P. L. Croot , H. J. W. de Baar , P. Laan , G. Sarthou , et al. Shipboard analytical intercomparison of dissolved iron in surface waters along a north-south transect of the Atlantic Ocean. Mar. Chem. 2003 , 84,  19.
        | Crossref | GoogleScholarGoogle Scholar |  open url image1

[13]   A. R. Bowie , E. P. Achterberg , P. L. Croot , H. J. W. de Baar , P. Laan , J. W. Moffett , S. Ussher , P. J. Worsfold , A community-wide intercomparison exercise for the determination of dissolved iron in seawater. Mar. Chem. 2006 , 98,  81.
        | Crossref | GoogleScholarGoogle Scholar |  open url image1

[14]   K. Johnson , E. Boyle , K. Bruland , C. Measures , J. Moffett , SAFe-team SAFe: sampling and analysis of iron in the ocean. Geophys. Res. Abstr. 2005 , 7,  05813.
         open url image1

[15]   A. R. Bowie , P. N. Sedwick , P. J. Worsfold , Analytical intercomparison between flow injection-chemiluminescence and flow injection-spectrophotometry for the determination of picomolar concentrations of iron in seawater. Limnol. Oceanogr. Methods 2004 , 2,  42.
         open url image1

[16]   A. R. Bowie , S. J. Ussher , W. M. Landing , P. J. Worsfold , Intercomparison between FI-CL and ICP-MS for the determination of dissolved iron in Atlantic seawater. Environ. Chem. 2007 , 4,  1.
        | Crossref | GoogleScholarGoogle Scholar |  open url image1

[17]   M. C. Lohan , A. M. Aguilar-Islas , K. W. Bruland , Direct determination of iron in acidified (pH 1.7) seawater samples by flow injection catalytic spectrophotometric detection: application and intercomparison. Limnol. Oceanogr. Methods 2006 , 4,  164.
         open url image1

[18]   A. R. Bowie , E. P. Achterberg , R. F. C. Mantoura , P. J. Worsfold , Determination of sub-nanomolar levels of iron in seawater using flow injection with chemiluminescence detection. Anal. Chim. Acta 1998 , 361,  189.
        | Crossref | GoogleScholarGoogle Scholar |  open url image1

[19]   I. Petrov , C. R. Quetel , Low uncertainty Fe isotope ratio measurements in sea-water samples by ICP-MS at medium mass resolution. J. Anal. At. Spectrom. 2005 , 20,  1095.
        | Crossref | GoogleScholarGoogle Scholar |  open url image1

[20]   I. Petrov , C. R. Quetel , P. D. P. Taylor , Investigation on sources of contamination, for an accurate analytical blank estimation, during measurements of the Fe content in seawater by isotope dilution inductively coupled plasma mass spectrometry. J. Anal. At. Spectrom. 2007 , 22,  608.
        | Crossref | GoogleScholarGoogle Scholar |  open url image1

[21]   BIPM, Comité Consultatif pour la Quantité de Matière 1995, report of the 1st meeting (Bureau International des Poids et Mesures: Paris, France).

[22]   M. J. T. Milton , T. J. Quinn , Primary methods for the measurement of amount of substance. Metrologia 2001 , 38,  289.
        | Crossref | GoogleScholarGoogle Scholar |  open url image1

[23]   A. Laes , S. Blain , P. Laan , S. J. Ussher , E. P. Achterberg , P. Treguer , H. J. W. de Baar , Sources and transport of dissolved iron and manganese along the continental margin of the Bay of Biscay. Biogeosciences 2007 , 4,  181.
         open url image1

[24]   S. J. Ussher , P. J. Worsfold , E. P. Achterberg , A. Laës , S. Blain , P. Laan , H. J. W. de Baar , Distribution and redox speciation of dissolved iron on the European Continental Margin. Limnol. Oceanogr. 2007 , 52,  2530.
         open url image1

[25]   S. B. Moran , P. A. Yeats , P. W. Balls , On the role of colloids in trace metal solid-solution partitioning in continental shelf waters: a comparison of model results and field data. Cont. Shelf Res. 1996 , 16,  397.
        | Crossref | GoogleScholarGoogle Scholar |  open url image1

[26]   M. Boye , A. P. Aldrich , C. M. G. Van den Berg , J. T. M. de Jong , M. Veldhuis , H. J. W. de Baar , Horizontal gradient of the chemical speciation of iron in surface waters of the northeast Atlantic Ocean. Mar. Chem. 2003 , 80,  129.
        | Crossref | GoogleScholarGoogle Scholar |  open url image1

[27]   Miller J. C., Miller J. N., Statistics for Analytical Chemistry 1993 (Ellis Horwood and Prentice Hall: London).

[28]   Fitting a linear functional relationship, AMC Technical Briefs (no. 10) 2002 (Royal Society of Chemistry: London).

[29]   S. J. Ussher , A. Milne , W. M. Landing , K. Attiq-ur-Rehman , M. J. M. Séguret , T. Holland , E. P. Achterberg , A. Nabi , P. J. Worsfold , Investigation of iron(III) reduction and trace metal interferences in the determination of dissolved iron in seawater using flow injection with luminol chemiluminescence detection. Anal. Chim. Acta 2009 , 652,  259.
        | Crossref | GoogleScholarGoogle Scholar |  open url image1

[30]   J. F. Wu , E. Boyle , W. Sunda , L. S. Wen , Soluble and colloidal iron in the oligotrophic North Atlantic and North Pacific. Science 2001 , 293,  847.
        | Crossref | GoogleScholarGoogle Scholar |  open url image1

[31]   J. F. Wu , E. A. Boyle , Determination of iron in seawater by high-resolution isotope dilution inductively coupled plasma mass spectrometry after Mg(OH) (2) coprecipitation. Anal. Chim. Acta 1998 , 367,  183.
        | Crossref | GoogleScholarGoogle Scholar |  open url image1

[32]   W. M. Landing , C. Haraldsson , N. Paxeus , Vinyl polymer agglomerate based transition-metal cation chelating ion-exchange resin containing the 8-hydroxyquinoline functional-group. Anal. Chem. 1986 , 58,  3031.
        | Crossref | GoogleScholarGoogle Scholar |  open url image1