Spectroelectrochemical sensing based on multimode selectivity simultaneously achievable in a single device. 6....

Area of Science:

• Electrochemistry
• Analytical Chemistry
• Materials Science

Background:

• Spectroelectrochemistry offers sensitive detection methods.
• Developing selective sensors for nonabsorbing analytes remains a challenge.
• Composite materials provide tunable properties for sensor applications.

Purpose of the Study:

• To demonstrate a mediator-based spectroelectrochemical sensor for nonabsorbing analytes.
• To utilize a charge-selective Nafion-SiO2 composite film for analyte detection.
• To optimize sensor performance by studying key parameters.

Main Methods:

• Fabrication of a Nafion-SiO2 composite film.
• Entrapment of a redox mediator (Ruthenium(II) tris(bipyridine), Ru(bipy)3(2+)).
• Spectroelectrochemical detection using attenuated total reflection (ATR).

Main Results:

• Successful detection of the nonabsorbing analyte, ascorbate.
• Observation of changes in absorbance (deltaA) correlated with analyte presence.
• Established optimal sensor conditions by varying scan rate, mediator concentration, and film thickness.
• Achieved a linear detection range from 0.26 to 2.0 mM with R² = 0.998.

Conclusions:

• The developed spectroelectrochemical sensor effectively detects nonabsorbing analytes.
• The Nafion-SiO2 composite film is suitable for entrapping mediators and enabling selective detection.
• The sensor demonstrates high linearity and sensitivity, paving the way for practical applications.