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Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O
Published on: October 7, 2020
Determination of ammonium using a microplate-based fluorometric technique.
Patrick Poulin1, Emilien Pelletier
1Institut des Sciences de la Mer de Rimouski (ISMER), Université du Québec à Rimouski, 310 allée des Ursulines, Rimouski, Que., Canada G5L 3A1.
Talanta
|December 17, 2008
Summary
A new fluorometric method accurately measures ammonium (NH4+) in complex waters, even with high particulate matter and organic acids. This technique offers reliable, automated readings for environmental monitoring.
Area of Science:
- Environmental Chemistry
- Analytical Chemistry
- Water Quality Monitoring
Background:
- Accurate ammonium (NH4+) determination is crucial for assessing water quality.
- Existing methods struggle with complex matrices like high suspended particulate matter and dissolved organic acids.
- Fresh and brackish waters present unique challenges due to variable salinity and background fluorescence.
Purpose of the Study:
- To present a novel microplate-based fluorometric technique for ammonium determination.
- To enable quick, automated readings in diverse water sample types.
- To validate the method's robustness against common environmental interferents.
Main Methods:
- Development of a microplate-based fluorometric assay.
- Automated sample processing and fluorescence reading.
- Determination of method's limit of detection (LOD) and repeatability using calibration curves.
Main Results:
- The technique achieved a lowest detectable concentration of 5 nM and a practical LOD of 50 nM.
- High levels of suspended particulate matter, organic acids, and salinity did not interfere with ammonium measurements.
- The method demonstrated excellent repeatability and accuracy across various water bodies.
Conclusions:
- The new fluorometric technique provides a robust and efficient tool for ammonium analysis in challenging aquatic environments.
- Application to St. Lawrence Estuary samples revealed significant ammonium sources from terrestrial and saltmarsh ecosystems.
- This method enhances the capacity for precise water quality assessment in estuarine and riverine systems.
