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

This study aims to investigate the applicability of a hybrid electrochemical sensor composed of cork and graphite (Gr) for detecting caffeine in aqueous solutions. Raw cork (RAC) and regranulated cork (RGC, obtained by thermal treatment of RAC with steam at 380 degrees C) were tested as modifiers. The results clearly showed that the cork-graphite sensors, GrRAC and GrRGC, exhibited a linear response over a wide range of caffeine concentration (5-1000 mu M), with R-2 of 0.99 and 0.98, respectively. The limits of detection (LOD), estimated at 2.9 and 6.1 mu M for GrRAC and GrRGC, suggest greater sensitivity and reproducibility than the unmodified conventional graphite sensor. The low-cost cork-graphite sensors were successfully applied in the determination of caffeine in soft drinks and pharmaceutical formulations, presenting well-defined current signals when analyzing real samples. When comparing electrochemical determinations and high performance liquid chromatography measurements, no significant differences were observed (mean accuracy 3.0%), highlighting the potential use of these sensors to determine caffeine in different samples.

Automated summary

The hybrid electrochemical sensor composed of cork and graphite showed high sensitivity and reproducibility for detecting caffeine in aqueous solutions, making it suitable for analyzing samples like soft drinks and pharmaceutical formulations. The cork-graphite sensors exhibited a wider linear response range and lower limits of detection compared to traditional graphite sensors. The electrochemical determinations showed high accuracy when compared with high performance liquid chromatography measurements, suggesting the potential use of these sensors for determining caffeine in different samples.