A selective molecularly imprinted polymer-carbon nanotube sensor for cotinine sensing

Area of Science:

• Materials Science
• Analytical Chemistry
• Nanotechnology

Background:

• Molecular imprinting is a powerful technique for creating selective recognition sites in polymers.
• Conductive composite films offer potential for sensitive sensor applications.
• Developing selective sensors for alkaloids like cotinine is crucial for various analytical needs.

Purpose of the Study:

• To create and characterize conductive composite films using single-walled carbon nanotubes and molecularly imprinted poly-4-vinylphenol.
• To evaluate the sensor's performance in detecting cotinine based on changes in electrical resistance.
• To assess the film's selectivity against structurally similar compounds, such as nicotine.

Main Methods:

• Fabrication of conductive composite films with single-walled carbon nanotubes coated with molecularly imprinted poly-4-vinylphenol.
• Characterization using ultraviolet and infrared spectroscopies.
• Electrical resistance measurements upon cotinine binding and desorption.
• Morphological analysis via scanning electron microscopy.
• Selectivity assessment using gas chromatography.

Main Results:

• Successful molecular imprinting of the poly-4-vinylphenol coating with cotinine was confirmed.
• The imprinted film exhibited a significant electrical resistance change (>30 kΩ) upon cotinine binding.
• The unimprinted film showed minimal response to cotinine.
• The film's resistance returned to baseline after cotinine desorption.
• Gas chromatography confirmed selective detection of cotinine over nicotine.

Conclusions:

• The developed conductive composite film demonstrates effective molecular imprinting for cotinine detection.
• The sensor exhibits high sensitivity and selectivity, with significant electrical response to cotinine.
• The reversible nature of the resistance change suggests potential for reusable sensor applications.