Reduced electrode polarization at electrode and analyte interface in impedance spectroscopy using carbon paste and...

Area of Science:

• Electrochemistry
• Materials Science
• Analytical Chemistry

Background:

• Electrode polarization (EP) at the electrode-analyte interface impedes impedance spectroscopy measurements, particularly at low frequencies for biological samples.
• Existing electrode materials and substrates present challenges in mitigating EP for accurate electrochemical analysis.

Purpose of the Study:

• To develop a novel carbon paste (CP) electrode material to reduce electrode polarization (EP).
• To investigate the efficacy of CP electrodes on a chromatography paper substrate for impedance spectroscopy.
• To compare the EP performance of CP electrodes against silver paste and pencil electrodes.

Main Methods:

• Fabrication of coplanar electrodes using carbon paste (pencil graphite and transparent glue), silver paste, and pencil electrodes on chromatography paper.
• Electrochemical impedance spectroscopy (EIS) to analyze electrode polarization.
• Equivalent electrical circuit modeling with constant phase elements to quantify EP.
• Cyclic voltammetry (CV) to assess electrode properties.

Main Results:

• The novel carbon paste electrode demonstrated significantly lower electrode polarization compared to silver paste and pencil electrodes.
• Cyclic voltammetry revealed a blocking electrode property of the carbon paste, reducing direct current flow.
• The chromatography paper substrate enhanced electrode surface roughness, increasing effective surface area and further reducing EP.

Conclusions:

• The developed carbon paste electrode on chromatography paper effectively minimizes electrode polarization in impedance spectroscopy.
• This novel electrode material offers improved performance for analyzing biological samples at lower frequencies.
• The combination of carbon paste and chromatography paper presents a promising approach for advanced electrochemical sensing applications.