A portable analyser for the measurement of ammonium in marine waters

Natchanon Amornthammarong, Jia Zhong Zhang, Peter B. Ortner, Jack Stamates, Michael Shoemaker, Michael W. Kindel

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


A portable ammonium analyser was developed and used to measure in situ ammonium in the marine environment. The analyser incorporates an improved LED photodiode-based fluorescence detector (LPFD). This system is more sensitive and considerably smaller than previous systems and incorporates a pre-filtering subsystem enabling measurements in turbid, sediment-laden waters. Over the typical range for ammonium in marine waters (0-10 μM), the response is linear (r2 = 0.9930) with a limit of detection (S/N ratio > 3) of 10 nM. The working range for marine waters is 0.05-10 μM. Repeatability is 0.3% (n = 10) at an ammonium level of 2 μM. Results from automated operation in 15 min cycles over 16 days had good overall precision (RSD = 3%, n = 660). The system was field tested at three shallow South Florida sites. Diurnal cycles and possibly a tidal influence were expressed in the concentration variability observed. This journal is

Original languageEnglish (US)
Pages (from-to)579-584
Number of pages6
JournalEnvironmental Sciences: Processes and Impacts
Issue number3
StatePublished - Mar 2013

ASJC Scopus subject areas

  • Environmental Chemistry
  • Public Health, Environmental and Occupational Health
  • Management, Monitoring, Policy and Law


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