Monteiro Mayra K S, Da Silva Djalma R, Quiroz Marco A, Vilar Vítor J P, Martínez-Huitle Carlos A, Dos Santos Elisama V
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.
Materials (Basel). 2020 Dec 24;14(1):37. doi: 10.3390/ma14010037.
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 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.
本研究旨在探究一种由软木和石墨（Gr）组成的混合电化学传感器在检测水溶液中咖啡因时的适用性。将原始软木（RAC）和再制粒软木（RGC，通过在380℃下用蒸汽对RAC进行热处理获得）作为改性剂进行测试。结果清楚地表明，软木-石墨传感器GrRAC和GrRGC在较宽的咖啡因浓度范围（5 - 1000 μM）内呈现线性响应，R值分别为0.99和0.98。GrRAC和GrRGC的检测限（LOD）估计分别为2.9和6.1 μM，这表明它们比未改性的传统石墨传感器具有更高的灵敏度和重现性。低成本的软木-石墨传感器成功应用于软饮料和药物制剂中咖啡因的测定，在分析实际样品时呈现出明确的电流信号。在比较电化学测定结果和高效液相色谱测量结果时，未观察到显著差异（平均准确度为3.0%），这突出了这些传感器在测定不同样品中咖啡因时的潜在用途。
