Dynamic Sensor Concept Combining Electrochemical pH Manipulation and Optical Sensing of Buffer Capacity

Area of Science:

• Analytical Chemistry
• Sensor Technology
• Electrochemistry

Background:

• Individual electrochemical and optical sensors have limitations.
• Combining methodologies offers synergistic advantages.
• A dynamic sensing concept for buffer capacity is needed.

Purpose of the Study:

• To develop a dynamic sensing concept for buffer capacity.
• To combine electrochemical and optical sensing for enhanced performance.
• To rapidly assess buffer species concentration and pKa values.

Main Methods:

• Utilized water electrolysis to modulate the pH microenvironment.
• Employed an optical pH sensor in a flow cell.
• Applied a nonequilibrium readout mode for dynamic measurements.
• Validated the method with theoretical simulations.

Main Results:

• Successfully assessed buffer species concentration in 1 minute.
• Enabled in situ determination of the apparent pKa of MOPS buffer.
• Demonstrated the effectiveness of the combinatory approach.

Conclusions:

• The dynamic, combinatory sensing approach offers rapid and accurate buffer capacity analysis.
• This method overcomes limitations of individual sensor types.
• The approach shows significant potential for analyzing other pH-active analytes.