A Microscale NO(3)(-) Biosensor for Environmental Applications
L H Larsen1, T Kjær, N P Revsbech
1Department of Microbial Ecology, Institute of Biological Sciences, University of Aarhus, Bd. 540, DK-8000 Aarhus C, Denmark.
Analytical Chemistry
|June 7, 2011
Summary
A novel biosensor effectively measures nitrate (NO(3)(-)) using denitrifying bacteria. This tool offers a sensitive, rapid, and stable method for studying nitrogen metabolism in aquatic environments.
Area of Science:
- Environmental science
- Biotechnology
- Analytical chemistry
Background:
- Nitrate (NO(3)(-)) is a crucial nutrient in aquatic ecosystems, but its accurate measurement can be challenging.
- Existing methods for nitrate detection may have limitations in sensitivity, response time, or applicability to natural samples.
Purpose of the Study:
- To develop and characterize a novel biosensor for the direct determination of nitrate concentrations.
- To assess the performance of the biosensor in terms of sensitivity, selectivity, response time, and operational stability.
Main Methods:
- Construction of a biosensor utilizing immobilized denitrifying bacteria lacking N(2)O reductase.
- Quantification of nitrous oxide (N(2)O) produced from nitrate reduction using an electrochemical transducer.
- Evaluation of sensor performance in freshwater and seawater across different temperatures.
Main Results:
- The biosensor demonstrated linear responses to nitrate in both freshwater and seawater with a detection limit of approximately 1 μM.
- Response times were rapid (15-60 s at room temperature).
- The sensor operated for 2-4 days due to diffusive electron donor supply, with nitrite (NO(2)(-)) and nitrous oxide (N(2)O) identified as potential interferents.
Conclusions:
- The developed NO(3)(-) biosensor is a valuable tool for in-situ monitoring of nitrate levels.
- Its sensitivity, rapid response, and operational stability make it suitable for studying nitrogen metabolism in natural environments.
- Further optimization may be needed to address interference from nitrite and nitrous oxide.
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