Decoding Proton-Coupled Electron Transfer Mechanism of Nicotine for Multi-Scenario Portable Electrochemical Sensing

Area of Science:

• Electrochemistry
• Computational Chemistry
• Analytical Chemistry

Background:

• Nicotine electroanalysis faces challenges due to complex interfacial processes impacting sensor performance.
• Understanding these processes is crucial for accurate nicotine detection across various sample types.

Purpose of the Study:

• To elucidate the proton-coupled electron transfer mechanism of nicotine at the electrode interface.
• To develop a versatile sensor for multi-scenario nicotine detection.
• To provide molecular-level insights into nicotine electrooxidation.

Main Methods:

• Development of a screen-printed electrochemical analysis strip.
• Electrochemical characterization across a pH range (5-9).
• Density Functional Theory (DFT) calculations including electrostatic potential, Fukui function, and transition state analysis.

Main Results:

• The study identified a pH-dependent (pH 5-9) 2H+/2e- coupling transfer mechanism for nicotine.
• DFT calculations provided insights into the electronic structure of protonated nicotine and its role in electrooxidation.
• Thermodynamic and electron transfer quantification supported reaction kinetics, revealing a hydroxyl-dominated synergistic electrooxidation mechanism.

Conclusions:

• The developed platform successfully decodes the complex interfacial mechanism of nicotine electroanalysis.
• This work establishes a universal research paradigm for proton-coupled systems.
• The sensor demonstrates broad applicability in industrial quality control and biomedical monitoring.