Layer-by-layer thin film-coated electrodes for electrocatalytic determination of ascorbic acid

Area of Science:

• Electrochemistry
• Materials Science
• Nanotechnology

Background:

• Layer-by-layer (LbL) deposition is a versatile technique for fabricating multilayer thin films.
• Poly(allylamine hydrochloride) (PAH) and carboxymethyl cellulose (CMC) are commonly used polyelectrolytes in LbL assembly.
• Ferricyanide ([Fe(CN)(6)](3-)) is a redox-active species often employed in electrochemical studies.

Purpose of the Study:

• To prepare multilayer thin films of PAH and CMC on a gold electrode.
• To investigate the confinement of ferricyanide ions within these films.
• To evaluate the potential of the modified electrode for electrocatalytic applications.

Main Methods:

• Fabrication of multilayer thin films using layer-by-layer deposition of PAH and CMC on a gold disk electrode.
• Confining ferricyanide ions within the PAH/CMC multilayer films under varying pH conditions.
• Electrochemical characterization using cyclic voltammetry.
• Electrocatalytic determination of ascorbic acid.

Main Results:

• Successful confinement of ferricyanide ions in PAH/CMC films from weakly acidic or neutral solutions.
• Observation of clear redox peaks for confined ferricyanide ions around 0.35V vs. Ag/AgCl.
• Dependence of confined ferricyanide ion concentration on film thickness (number of layers).
• Demonstration of electrocatalytic determination of ascorbic acid in the 1-50mM range.

Conclusions:

• PAH/CMC multilayer films can effectively confine ferricyanide ions.
• The pH of the solution plays a crucial role in the ion confinement process.
• The modified electrode shows promise for the sensitive determination of ascorbic acid.