Modified stainless steel microneedle electrode for polyphenolics detection.

Area of Science:

• Electrochemistry
• Materials Science
• Analytical Chemistry

Background:

• Polyphenols are vital plant compounds with significant health benefits.
• Accurate and real-time monitoring of polyphenols is crucial for food quality and health assessments.
• Existing methods for polyphenol analysis can be complex and time-consuming.

Purpose of the Study:

• To develop a simple, sensitive microneedle electrode for plant polyphenol monitoring.
• To enable in-situ and minimally invasive analysis of antioxidants in real samples.
• To investigate the potential of microneedle electrodes for depth profiling of antioxidant content.

Main Methods:

• Fabrication of microneedle electrodes using layer-by-layer assembly of carbon nanotubes, cellulose nanocrystals, polyaniline, and a silane binding agent.
• Characterization using SEM, EIS, FTIR, and Raman spectroscopy.
• Capacitive detection of gallic acid and chlorogenic acid, followed by application to orange juice samples.

Main Results:

• The microneedle electrodes demonstrated successful capacitive detection of gallic acid and chlorogenic acid.
• Linear detection ranges were established: 0.1-87.23 μg/mL for gallic acid and 0.1-78.01 μg/mL for chlorogenic acid.
• Low detection limits were achieved (0.29 ± 0.2 μg/mL for GA, 0.34 ± 0.2 μg/mL for CA), with successful application in orange juice and depth profiling.

Conclusions:

• The developed microneedle electrode is a promising tool for sensitive, real-time monitoring of plant polyphenols.
• The minimally invasive nature of the technology allows for in-situ analysis in various fruit matrices.
• Microneedle electrodes show potential for depth profiling of antioxidant content in food samples.