Graphitic Carbon Nitride-Wrapped Metal-free PoPD-Based Biosensor for Xanthine Detection

Area of Science:

• Electrochemistry
• Materials Science
• Biosensors

Background:

• Xanthine (Xn) determination is crucial for assessing food quality and spoilage.
• Existing biosensors often rely on metal-based catalysts, posing environmental and cost concerns.

Purpose of the Study:

• To develop a novel, metal-free enzymatic biosensor for accurate xanthine detection.
• To utilize a unique nanocomposite of graphitic carbon nitride (g-C3N4) and poly-ortho-phenylenediamine (PoPD) for enhanced sensing capabilities.

Main Methods:

• Fabrication of a PoPD@g-C3N4 nanocomposite.
• Characterization using Field Emission Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and X-ray Diffraction.
• Electrochemical analysis via Cyclic Voltammetry and Electrochemical Impedance Spectroscopy.

Main Results:

• The PoPD@g-C3N4 nanocomposite demonstrated excellent electrochemical properties.
• The biosensor achieved high sensitivity (5.798 μAM⁻¹) with a rapid response time (5 s) at pH 7.5.
• A wide linear detection range (1 nM to 1 μM) and a low detection limit (0.001 nM) for xanthine were achieved.
• The biosensor exhibited good stability (4 weeks) and selectivity against interfering substances.
• Successful validation in real fish samples (Rohu, Labeo rohita) confirmed its practical applicability.

Conclusions:

• The developed metal-free PoPD@g-C3N4 biosensor offers a highly sensitive, stable, and reproducible platform for xanthine detection.
• This biosensor shows significant potential for practical applications in food safety and quality control, particularly for analyzing xanthine in meat products.