Applicability of Cork as Novel Modifiers to Develop Electrochemical Sensor for Caffeine Determination

Area of Science:

• Electrochemistry
• Materials Science
• Analytical Chemistry

Background:

• Caffeine detection is crucial in food and pharmaceutical analysis.
• Developing cost-effective and sensitive sensors is an ongoing challenge.
• Electrochemical sensors offer a promising platform for analyte quantification.

Purpose of the Study:

• To evaluate a hybrid electrochemical sensor made of cork and graphite (Gr) for caffeine detection.
• To assess the performance of sensors modified with raw cork (RAC) and regranulated cork (RGC).
• To determine the sensor's applicability in real samples like soft drinks and pharmaceuticals.

Main Methods:

• Fabrication of cork-graphite hybrid sensors (GrRAC and GrRGC).
• Electrochemical analysis of caffeine in aqueous solutions across a concentration range of 5-1000 µM.
• Determination of limit of detection (LOD) and sensor reproducibility.
• Validation using soft drinks and pharmaceutical formulations.
• Comparison with High Performance Liquid Chromatography (HPLC) measurements.

Main Results:

• Both GrRAC and GrRGC sensors showed excellent linearity (R² > 0.98) for caffeine detection.
• Lower LOD values (2.9 µM for GrRAC, 6.1 µM for GrRGC) indicated high sensitivity compared to unmodified graphite.
• The sensors successfully detected caffeine in soft drinks and pharmaceuticals with clear signals.
• Accuracy was high (mean 3.0%) when compared to HPLC, demonstrating reliability.

Conclusions:

• Hybrid cork-graphite electrochemical sensors are effective for sensitive and accurate caffeine determination.
• The low-cost nature and successful application in real samples highlight their practical potential.
• These sensors offer a viable alternative to conventional methods for caffeine analysis.