Ocean Dynamics

, Volume 61, Issue 10, pp 1555–1565 | Cite as

A high-resolution analyser for the measurement of ammonium in oligotrophic seawater

  • Samer K. Abi Kaed Bey
  • Douglas P. Connelly
  • François-Eric Legiret
  • Andy J. K. Harris
  • Matthew C. Mowlem
Part of the following topical collections:
  1. Topical Collection on Multiparametric observation and analysis of the Sea


In this work, we describe a high-resolution fluorometric shipboard analyser and an improved method to determine NH 4 + in oligotrophic seawater. The limit of detection is <5 nM, calculated with 95% confidence level using the weighted regression line applied to the standard addition method using real samples prepared with low nutrient seawater from the Atlantic. The results are summarised and cross-compared with spiked artificial seawater (ASW) and spiked Milli-Q water samples. The analyser has a precision of ±1–4% with a high performance over a wide range from 5 nM to 25 μM. The methodology of NH 4 + analysis is based on the fluorescent product formed between o-pthaldialdehyde and NH 4 + in the presence of sulfite. Due to the high resolution of the developed system, we were able to study in depth the sensitivity of the method to salinity, amines, amino acids and potential interferences from particles/algae. The method was found to be sensitive to salinity variations, reducing the signal by up to 85% at 5 nM; this effect decreased at higher concentrations of ammonium. It was noted that the interference from amines at low concentrations was negligible; however, at either high amino acid or high amine concentrations, the signal was depressed. To test for the effect of particles on the system, the system was tested with samples containing phytoplankton (Dunaliella primolecta) cells at different concentrations prepared with ASW to simulate the effect of a phytoplankton bloom. This experiment assessed the potential impact of both particles and other potential fluorescence interferences from cells and/or ammonium leaching from cells. This experiment showed that a phytoplankton bloom could potentially have an impact of up to 12% on the signal of interest. Thus, we propose that this method is suitable for oligotrophic environments rather than coastal and eutrophic environments. The reagent was found to be stable for 17 days and standards of 1 μM were stable for 6 days under laboratory conditions. The developed analyser was successfully demonstrated in the North Atlantic Ocean, in an area of oligotrophic, low NH 4 + oceanic waters.


Ammonium Shipboard Analyser Fluorometric Resolution 



This research is funded by the UK Natural Environment Research Council Oceans 2025 theme 5 & 8.1 research programme. This work is also supported by SENSEnet, a Marie Curie Initial Training Network (ITN) funded by the European Commission Seventh Framework Programme, Contract Number PITN-GA-2009-237868. The authors wish to thank Prof. Ralf Prien, Dr. Cedric Flouquet, Dr. Maria-Nefeli Tsaloglou and Dr. Sarah Bennett for their useful guidance during the experimental phases of this work and comments on this manuscript. Thanks also to Lee Fowler, Jennifer Riley, Catherine Burd, Bahi Mahadji, Dr. David Barat and Ed Smith for their help during the laboratory and field studies.


  1. American Public Health Association (1985) Standard methods for examination of water and wastewater, 16th edn. American Public Health Association, Washington, DCGoogle Scholar
  2. ASTM (American Society for Testing and Materials) (1996) D5810: standard guide for spiking into aqueous samples. American Society for Testing and Materials, West ConshohockenGoogle Scholar
  3. Aminot A, Kerouel R, Birot D (2001) A flow injectionfluorometric method for the determination of ammonium in fresh and saline waters with a view to in situ analyses. Elsevier 35:1777–1785Google Scholar
  4. Aminot A, Kérouel R (2006) The determination of total dissolved free primary amines in seawater: critical factors, optimized procedure and artefact correction. Marine Chemistry 98:223–240CrossRefGoogle Scholar
  5. Amornthammarong N, Zhang JZ (2008) Shipboard fluorometric flow analyzer for high-resolution underway measurement of ammonium in seawater. Anal Chem 80:1019–1026CrossRefGoogle Scholar
  6. Aoki T, Uemura S, Munemori M (1983) Continuous flow fluorometric determination of ammonia in water. Anal Chem 55:1620–1622CrossRefGoogle Scholar
  7. Azmi N, Ahmad M, Abdullah J, Sidek H, Heng L, Karuppiah N (2009) Biosensor based on glutamate dehydrogenase immobilized in chitosan for the determination of ammonium in water samples. Anal Biochem 388:28–32CrossRefGoogle Scholar
  8. Bader M (1980) A systematic approach to standard addition methods in instrumental analysis. J Chem Educ 37:794–798Google Scholar
  9. Brzezinski MA (1988) Vertical distribution of ammonium in stratified oligotrophic waters. Limnol Oceanogr 33(5):1176–1182CrossRefGoogle Scholar
  10. Cooper C, Packer N, Williams K (2001) Methods in molecular biology: amino acids analysis protocols 159. Humana, Totowa, p 138Google Scholar
  11. Eaton AD, Clesceri LS, Rice EW et al (2005) Standard methods for examination of water and wastewater, 21st edn. American Technical, New YorkGoogle Scholar
  12. Frank C, Schroeder F (2007) Using sequential injection analysis to improve system and data reliability of online methods: determination of ammonium and phosphate in coastal waters. J Automated Meth Manag Chem. doi: 10.1155/2007/49535
  13. Garcia-Rubio LH (1992) Refractive index effects on the absorption spectra of macromolecules. Macromolecules 25:2608–2613CrossRefGoogle Scholar
  14. Genfa Z, Dasgupta P (1989) Fluorometric measurement of aqueous ammonium ion in a flow injection system. Anal Chem 61:408–412CrossRefGoogle Scholar
  15. Goyal SS, Rains DW, Huffaker RC (1988) Determination of ammonium ion by fluorometry or spectrophotometry after on-line derivatization with o-phthalaldehyde. Anal Chem 60:175–179CrossRefGoogle Scholar
  16. Gray S, Ellis P, Grace M, McKelvie I (2006) Spectrophotometric determination of ammonia in estuarine waters by hybrid reagent-injection gas-diffusion flow analysis. Spectrosc Lett 39:737–753CrossRefGoogle Scholar
  17. Harbin AM, Van den Berg CMG (1993) Determination of ammonia in seawater using catalytic cathodic stripping voltammetry. Anal Chem 65:3411–3416CrossRefGoogle Scholar
  18. Holmes RM, Aminot A, Kérouel R, Hooker BA, Peterson BJ (1999) A simple and precise method for measuring ammonium in marine and freshwater ecosystems. Can J Fish Aquat Sci 56:1801–1808Google Scholar
  19. Keith LH, Crummett W, Deegan JJ, Libby RA, Taylor JK, Wentler G (1983) Principles of environmental analysis. Anal Chem 55:2210–2218CrossRefGoogle Scholar
  20. Kérouel R, Aminot A (1997) Fluorometric determination of ammonia in sea and estuarine waters by direct segmented flow analysis. Mar Chem 57:265–275CrossRefGoogle Scholar
  21. Li Q, Zhang JZ, Millero F, Hansell D (2005) Continuous colorimetric determination of trace ammonium in seawater with a long-path liquid waveguide capillary cell. Mar Chem 96:73–85CrossRefGoogle Scholar
  22. Meseguer-Lloret S, Molins-Legua C, Campins-Falco P (2002) Ammonium determination in water samples by using OPA-NAC reagent: a comparative study with Nessler and ammonium selective electrode methods. Int J Environ Anal Chem 82:475–489CrossRefGoogle Scholar
  23. Mikkelsen O, Milligan T, Hill P, Chant R, Jago C, Jones S, Vladimir K, Mitchelson-Jacob G (2008) The influence of schlieren on in situ optical measurements used for particle characterization. Limnol Oceanogr Meth 6:133–143CrossRefGoogle Scholar
  24. Polaina J, MacCabe AP (eds) (2007) Industrial enzymes: structure, function, and applications. ISBN 978-1-4020-5376-4, Springer, New YorkGoogle Scholar
  25. Plant JN, Johnson KS, Needoba JA, Coletti LJ (2009) NH4-Digiscan: an in situ and laboratory ammonium analyzer for estuarine, coastal and shelf waters. Limnol Oceanogr Meth 7:144–156CrossRefGoogle Scholar
  26. Rees AP, Woodward EMS, Joint I (2006) Concentrations and uptake of nitrate and ammonium in the Atlantic Ocean between 60°N and 50°S. Deep-Sea Research II 53:1649–1665CrossRefGoogle Scholar
  27. Roth M (1971) Fluorescence reaction for amino acids. Anal Chem 43:880–882CrossRefGoogle Scholar
  28. Solorzano L (1969) Determination of ammonia in natural waters by the phenolhypochlorite method. Limnol Oceanogr 14:799–801CrossRefGoogle Scholar
  29. Taylor JK (1989) Quality assurance of chemical measurements. 6th edition. Lewis, Chelsea, MichiganGoogle Scholar
  30. Taylor BW, Christine FK, Hall RO Jr, Koch J, Tronstad LM (2007) Improving the fluorometric ammonium method: matrix effects, background fluorescence, and standard additions. Benthol. Soc. 26:167–177Google Scholar
  31. Timmer B, Olthuis W, van den Berg A (2005) Ammonia sensors and their applications—a review. Sensors and Actuators B 107:666–677CrossRefGoogle Scholar
  32. Uriarte I, Farias A, Hawkins AJS, Bayne BL (1993) Cell characteristics and biochemical composition of Dunaliella primolecta Butcher conditioned at different concentrations of dissolved nitrogen. J of Appl Phycol 5:447–453CrossRefGoogle Scholar
  33. Watson R, Butler E, Clementson L, Berry K (2004) Flow-injection analysis with fluorescence detection for the determination of trace levels of ammonium in seawater. J Environ Monit 7:37–42CrossRefGoogle Scholar
  34. Yang X-H, Scranton MJ, Lee C (1994) Seasonal variations in concentration and microbial uptake of methylamines in estuarine waters. Mar Ecol Prog Ser 108:303–312CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Samer K. Abi Kaed Bey
    • 1
  • Douglas P. Connelly
    • 1
  • François-Eric Legiret
    • 1
  • Andy J. K. Harris
    • 1
  • Matthew C. Mowlem
    • 1
  1. 1.National Oceanography CentreUniversity of Southampton—Waterfront CampusSouthamptonUK

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