| Autor: |
Monteiro MKS; Laboratório de Eletroquímica Ambiental e Aplicada, Universidade Federal do Rio Grande do Norte, Lagoa Nova 59.072-900, Brazil., Da Silva DR; Laboratório de Eletroquímica Ambiental e Aplicada, Universidade Federal do Rio Grande do Norte, Lagoa Nova 59.072-900, Brazil., Quiroz MA; Laboratório de Eletroquímica Ambiental e Aplicada, Universidade Federal do Rio Grande do Norte, Lagoa Nova 59.072-900, Brazil.; Grupo de Investigación en Energía y Ambiente, Universidad de las Américas Puebla, ExHda. Sta. Catarina Martir, Cholula 72820, Mexico., Vilar VJP; Laboratory of Separation and Reaction Engineering-Laboratory of Catalysis and Materials (LSRE-LCM), Chemical Engineering Department, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal., Martínez-Huitle CA; Laboratório de Eletroquímica Ambiental e Aplicada, Universidade Federal do Rio Grande do Norte, Lagoa Nova 59.072-900, Brazil.; National Institute for Alternative Technologies of Detection, Toxicological Evaluation and Removal of Micropollutants and Radioactives (INCT-DATREM), Institute of Chemistry, UNESP, P.O. Box 355, Araraquara 14800 900, Brazil., Dos Santos EV; Laboratório de Eletroquímica Ambiental e Aplicada, Universidade Federal do Rio Grande do Norte, Lagoa Nova 59.072-900, Brazil.; National Institute for Alternative Technologies of Detection, Toxicological Evaluation and Removal of Micropollutants and Radioactives (INCT-DATREM), Institute of Chemistry, UNESP, P.O. Box 355, Araraquara 14800 900, Brazil. |
| Abstrakt: |
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 °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 µM), with R 2 of 0.99 and 0.98, respectively. The limits of detection (LOD), estimated at 2.9 and 6.1 µM 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. |
