Direct detection of acidity, alkalinity, and pH with membrane electrodes
Gastón A Crespo1, Majid Ghahraman Afshar, Eric Bakker
1Department of Inorganic, Analytical and Applied Chemistry, University of Geneva, Switzerland.
Analytical Chemistry
|November 13, 2012
Summary
A novel electrochemical sensor using supported liquid ion-selective membranes directly measures total alkalinity in samples with weak bases. This method, based on chronopotentiometry, offers a new tool for in situ water quality analysis.
Area of Science:
- Electrochemistry
- Analytical Chemistry
- Environmental Science
Background:
- Accurate determination of total alkalinity is crucial for understanding water chemistry and quality.
- Existing methods for alkalinity measurement can be complex or unsuitable for in situ applications.
Purpose of the Study:
- To present a novel electrochemical sensing protocol for the direct detection of total alkalinity.
- To demonstrate the versatility of the developed sensor for measuring pH, acidity, and alkalinity.
Main Methods:
- Utilized supported liquid ion-selective membranes for electrochemical sensing.
- Employed chronopotentiometry to determine alkalinity by measuring transition time related to ion depletion.
- Applied zero-current potentiometry for pH determination.
Main Results:
- Successfully developed and validated an electrochemical method for total alkalinity detection in samples containing weak bases like Tris.
- Demonstrated that the same membrane can be used for simultaneous or sequential measurement of pH, acidity, and alkalinity.
- The chronopotentiometric detection mode effectively relates transition time to sample alkalinity.
Conclusions:
- The developed electrochemical sensing protocol offers a direct and potentially in situ method for assessing water alkalinity.
- This versatile sensor technology holds promise for real-time environmental monitoring and water quality assessment in complex matrices.
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