Electrodeposition of 4-Benzenesulfonic Acid onto a Graphite-Epoxy Composite Electrode for the Enhanced Voltammetric Determination of Caffeine in Beverages

Abstract

Caffeine is widely present in food and drinks, such as teas and coffees, being also part of some currently commercialized medicines, but despite its enhancement on several functions of human body, its exceeding use can promote many health problems. In order to develop new fast approaches for the caffeine sensing, graphite-epoxy composite electrodes (GECE) were used as substrate, being modified by different diazonium salts, synthetized as their tetraflouroborate salts. An analytical method for caffeine quantification was developed, using sware wave voltammetry (SWV) in Britton–Robinson buffer pH 2.0. Detection limits for bare electrode and 4-benzenesulfonic modified electrode were observed circa 145 µmol·L−1 and 1.3 µmol·L−1, respectively. The results have shown that the modification shifts the oxidation peaks to lower potential. Kinetics of the reaction limited by diffusion was more expressive when caffeine was added to the solution, resulting in decreases of impedance, characterized by lower Rct. All results for caffeine determination were compared to a reference chromatographic procedure (HPLC), showing no statistical difference. Analytical parameters for validation were suitably determined according to local legislation, leading to a linear behaviour from 5 to 150 µmol·L−1; precision of 4.09% was evaluated based on the RDC 166/17, and accuracy was evaluated in comparison with the reference method, with recovery of 98.37 ± 2.58%.

Recent Development of Nano-Carbon Material in Pharmaceutical Application: A Review

“…However, caffeine in high concentrations is toxic to the body and can cause nausea, shaking, hyperactivity, nervousness, and even death when consumed at concentrations above 200 mg/day. [ 77 , 78 , 79 , 80 , 81 ]. This sensor is made by drop-coating method.…”

Fullerene/MWCNT/Nafion Modified Glassy Carbon Electrode for the Electrochemical Determination of Caffeine

“…Most neuroprotective and metabolic benefits commonly associated with coffee and tea consumption have often been linked to caffeine content of these beverages [3]. Caffeine promotes gastric acid secretion and diuresis; and stimulates the central nervous [4] [5] [6] and the cardiovascular systems [7] [8]. It is however known that a high concentration of caffeine is toxic for the human body: it can cause nausea, trembling, nervousness, depression, hyperactivity and mutation effects [7] [9].…”

“…It is however known that a high concentration of caffeine is toxic for the human body: it can cause nausea, trembling, nervousness, depression, hyperactivity and mutation effects [7] [9]. It constitutes a risk factor for cardiovascular diseases and asthma disease [4] [10]. The consumption of caffeine above 200 mg/day may lead to death [11].…”