A Sensitive Micro Conductometric Ethanol Sensor Based on an Alcohol Dehydrogenase-Gold Nanoparticle Chitosan...

Area of Science:

• Electrochemistry
• Biosensors
• Nanomaterials

Background:

• Ethanol detection is crucial for various applications, including medical diagnostics and quality control.
• Existing sensors often face limitations in sensitivity, selectivity, and response time.
• Chitosan-based composites offer a promising platform for biosensor development.

Purpose of the Study:

• To design and develop a novel microconductometric sensor for ethanol detection.
• To investigate the role of gold nanoparticles (GNPs) in enhancing sensor performance.
• To evaluate the sensor's analytical characteristics, including response time, sensitivity, selectivity, and reproducibility.

Main Methods:

• Fabrication of a chitosan composite sensor incorporating alcohol dehydrogenase and its cofactor.
• Immobilization of gold nanoparticles (GNPs) onto the chitosan matrix.
• Calibration of the sensor using differential measurements in the headspace of aqueous ethanol solutions.
• Assessment of sensor performance with and without GNPs, including response time, sensitivity, selectivity (vs. methanol), and reproducibility (RSD).

Main Results:

• The inclusion of GNPs significantly improved sensor performance.
• Response time decreased from 21 s to 10 s with GNPs.
• Sensitivity increased by 11.3 times (416 µS/cm (v/v)⁻¹) with GNPs.
• Selectivity factor versus methanol improved by three times (8.3) with GNPs.
• Reproducibility (RSD) improved from 12% to 2% with GNPs.
• The sensor detected high ethanol levels (3.5 v/v%) in human breath after mouthwash use.

Conclusions:

• Gold nanoparticles are crucial for enhancing the analytical performance of chitosan-based microconductometric ethanol sensors.
• The developed sensor demonstrates rapid response, high sensitivity, excellent selectivity, and superior reproducibility.
• The sensor shows potential for practical applications, such as detecting ethanol in biological samples.