Closed bipolar electrode-enabled dual-cell electrochromic detectors for chemical sensing

Area of Science:

• Electrochemistry
• Analytical Chemistry
• Sensing Technologies

Background:

• Bipolar electrodes (BPEs) facilitate coupled redox reactions via electron transfer.
• Optical readout of electrochemical reactions is possible using reporter systems.
• Existing electrochemical sensors can be complex and lack portability.

Purpose of the Study:

• To develop a field-deployable electrochemical sensing method using bipolar electrodes and an electrochromic reporter.
• To characterize the sensor's performance for detecting various analytes.
• To demonstrate the device's portability and ability to analyze analytes in different phases.

Main Methods:

• Fabrication of BPE devices with two thin-layer cells (ITO and Pt).
• Coupling an analytical reaction with a methyl viologen (MV) reporter reaction for color change.
• Detection using microscopy with CCD camera and smartphone-based RGB analysis.
• Replacing potentiostat with batteries for portable potential control.

Main Results:

• Linear relationship observed between analyte concentration and colorimetric response for Fe(CN)63/4-, dopamine, and acetaminophen.
• Achieved a limit of detection of 1.0 μM for the model analyte.
• Demonstrated successful detection of ferrocene in acetonitrile using an aqueous MV reporter, showcasing phase separation capability.

Conclusions:

• The developed BPE sensor offers a simple, portable, and sensitive method for electrochemical sensing.
• The device's design allows for the detection of analytes in diverse chemical environments.
• This technology holds promise for field-deployable analytical applications.