Reagentless Acid-Base Titration for Alkalinity Detection in Seawater

Area of Science:

• Electroanalytical Chemistry
• Environmental Science
• Materials Science

Background:

• Traditional acid-base titrations can be time-consuming and require manual operation.
• Polyaniline (PANI) films have been identified as effective materials for rapid proton release.
• Automated, in situ water quality monitoring is essential for environmental management.

Purpose of the Study:

• To develop and validate a reagentless electroanalytical methodology for automated acid-base titrations.
• To utilize polyaniline films as an alkalinity sensor for water samples.
• To demonstrate the analytical utility and advantages of the new method for environmental applications.

Main Methods:

• A reagentless electroanalytical approach employing polyaniline films for proton release.
• Titration of water samples to a target pH of 4.0 to determine alkalinity.
• Validation of the method using Baltic Sea water samples and comparison with classical titrations.

Main Results:

• The methodology accurately measures alkalinity based on the charge released from PANI films, showing a linear relationship with bicarbonate concentration.
• Alkalinity measurements agreed well with classical methods (<10% discrepancy).
• Titrations were completed in under 1 minute, with reusable PANI films and potential for pH adjustment down to 2.

Conclusions:

• The developed electroanalytical methodology offers a rapid, automated, and reagentless approach for acid-base titrations and alkalinity sensing.
• The PANI-based sensor is reusable and efficient, suitable for both discrete and continuous monitoring.
• This innovation is poised to advance the digitalization of in situ water quality monitoring, enabling high-resolution alkalinity data collection.