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An ammonia-sensing air gap microelectrode.
1Department of Physiology, University of Pennsylvania, Philadelphia 19104.
Analytical Biochemistry
|November 1, 1988
Summary
A novel ammonia-sensing microelectrode was developed for detecting ammonium and urea. This simple, long-lasting sensor offers rapid and linear responses, demonstrating its potential for environmental and biological monitoring.
Area of Science:
- Electrochemistry
- Chemical Sensing
- Microfabrication
Background:
- Ammonia and urea detection are crucial in environmental and biomedical fields.
- Existing sensors often face challenges with sensitivity, response time, or fabrication complexity.
- There is a need for miniaturized, reliable sensors for real-time monitoring.
Purpose of the Study:
- To design and fabricate a novel air gap microelectrode for ammonia sensing.
- To develop a microsensor for urea detection based on the ammonia-sensing electrode.
- To evaluate the performance characteristics of the developed sensors.
Main Methods:
- Fabrication of an air gap microelectrode utilizing a neutral carrier pH-sensing inner electrode.
- Immobilization of urease enzyme within the microelectrode tip to create a urea microsensor.
- Electrochemical characterization of the sensors' response to ammonium and urea.
Main Results:
- The ammonia-sensing microelectrode exhibited a linear response to ammonium from 3 x 10(-5) to 10(-2) M.
- The sensor demonstrated a rapid response time (95%) of 10 to 15 seconds.
- The urea microsensor showed a linear response to urea from 3 x 10(-4) to 10(-2) M with a response time of 15 to 20 seconds.
Conclusions:
- A simple, easily fabricated air gap microelectrode with a long shelf life was successfully developed for ammonia sensing.
- The developed microelectrode can be readily converted into a urea microsensor via enzyme immobilization.
- These microsensors offer promising characteristics for sensitive and rapid detection of ammonium and urea.