Biosensor for chlorogenic acid based on an ionic liquid containing iridium nanoparticles and polyphenol oxidase

Area of Science:

• Electrochemistry
• Biosensor Technology
• Analytical Chemistry

Background:

• Chlorogenic acid is a significant compound in coffee with various health implications.
• Accurate quantification of chlorogenic acid is crucial for quality control and research.
• Existing analytical methods may require complex sample preparation or specialized equipment.

Purpose of the Study:

• To develop and validate a novel electrochemical biosensor for chlorogenic acid determination.
• To utilize polyphenol oxidase immobilized on chitosan and iridium nanoparticles for enhanced sensitivity.
• To assess the biosensor's performance in real coffee samples.

Main Methods:

• Construction of a biosensor using ionic liquid (1-n-butyl-3-methylimidazolium hexafluorophosphate), iridium nanoparticles, and immobilized polyphenol oxidase from sugar apple.
• Enzyme immobilization in chitosan crosslinked with oxalate.
• Electrochemical determination of chlorogenic acid using square wave voltammetry.
• Optimization of operational conditions for the biosensor.

Main Results:

• The biosensor exhibited a linear response for chlorogenic acid in the range of 3.48x10⁻⁶ to 4.95x10⁻⁵ mol L⁻¹.
• A low detection limit of 9.15x10⁻⁷ mol L⁻¹ was achieved.
• The biosensor demonstrated high recovery rates (93.2-105.7%) when applied to organic and decaffeinated coffee samples.
• Results showed good agreement with capillary electrophoresis methods.

Conclusions:

• The developed Ir-BMI.PF(6)/polyphenol oxidase biosensor is a sensitive and reliable tool for chlorogenic acid quantification.
• This biosensor offers a practical alternative for analyzing chlorogenic acid in food matrices like coffee.
• The use of ionic liquid and iridium nanoparticles enhances the biosensor's electrochemical performance.