An amperometric xanthine oxidase enzyme electrode based on hydrogen peroxide electroreduction

Area of Science:

• Electrochemistry
• Biotechnology
• Analytical Chemistry

Background:

• Xanthine oxidase is crucial in purine metabolism.
• Accurate quantification of xanthine is important for diagnosing certain diseases.
• Existing methods for xanthine detection can be limited by interference and sensitivity.

Purpose of the Study:

• To develop a novel xanthine oxidase enzyme electrode for quantitative xanthine analysis.
• To investigate the electrochemical detection mechanism.
• To assess the electrode's performance, including sensitivity, linearity, and interference effects.

Main Methods:

• Immobilization of xanthine oxidase onto an electrochemically modified graphite electrode.
• Coating the electrode surface with gelatine.
• Electrochemical detection based on the electroreduction of hydrogen peroxide.
• Amperometric measurements at a working potential of -50 mV (vs. Ag/AgCl).

Main Results:

• The developed electrode demonstrated a detection limit of 4.5 microM for xanthine.
• Linearity of the amperometric signal was observed up to approximately 40 microM xanthine.
• The electrode showed minimal interference from L-ascorbic and uric acid at the working potential.
• The response time of the sensor was less than 2 minutes.

Conclusions:

• The proposed xanthine oxidase enzyme electrode is a viable tool for the quantitative analysis of xanthine.
• The sensor exhibits good sensitivity, linearity, and selectivity.
• This electrochemical approach offers a rapid and reliable method for xanthine determination.