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

Abstract

Herein, a convenient method based on a fullerene/multiwalled carbon nanotube/Nafion modified glassy carbon electrode (fullerene/MWCNT/Naf/GCE) for the electrochemical determination of caffeine (CAF) is reported. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to study ionic exchange properties and conductivity the proposed electrode using [Fe(CN) 6 ] 3−/4− redox couple. Caffeine gave an irreversible oxidation peak around +1.33 V (vs. Ag/AgCl reference electrode) in HClO 4 (pH 1). The linear dependence of the peak current with the square root of the scan rate showed that the electron transfer process is controlled by diffusion. After optimization of key analytical parameters involved in differential pulse voltammetry (DPV), the oxidation peak current varied linearly with CAF concentration in the range of 10 to 1000 µM. A detection limit of 7.289 × 10 −8 M (S/N = 3) was found. Kinetic and chronocoulometric studies were also performed to characterize the diffusion of CAF. The developed electrode exhibited good stability and was easily regenerated. The influence of some potential interfering compounds such as dopamine, uric acid, glucose and sulfite ions on the anodic peak current of CAF was also examined. The proposed method was successfully employed in the determination of CAF in some commercial drugs.

Signal amplification by electropolymerization of alizarin red S for improved diuron detection at organosmectite modified glassy carbon electrode

“…[5,[11][12][13] However, the use of electrochemical sensors has increasingly attracted attention in recent years, due to attributes such as high stability, sensitivity, and selectivity. Compared with others, electrochemical methods are fast, inexpensive, miniaturizable, and offer good reproducibility, especially when the electrode is modified with materials including graphene oxide, [14] carbon nanotube, [15] conducting polymer, [16] clays, and organoclays. [17][18][19][20][21][22][23] Materials selected to be used in this study are organosmectite (since the raw clay is natural, abundant, and cheaper) and alizarin red S.…”

Interference-free Detection of Caffeine in Complex Matrices Using a Nanochannel Electrode Modified with Binary Hydrophilic–Hydrophobic PDMS

“…The performance of the developed electrode was compared with that of previous studies, as shown in Table S1. − ,− The developed p -PDMS-modified nanochannel electrodes show high sensitivity toward caffeine detection, with an LOD lower than most work reported before. Furthermore, the developed electrochemical sensors possess excellent anti-interference performance in real complex food samples.…”

“…Furthermore, the developed electrochemical sensors possess excellent anti-interference performance in real complex food samples. It has been reported that electrochemical detection of caffeine was easily affected by the food components such as dopamine, ascorbic acid, and l -dopa. ,, Without the interference of these substances, even a trace amount of caffeine could be detected in unprocessed samples by developed sensors. Although some studies have applied modified electrodes for real caffeinate sample analysis, the electrochemical curves in crude food were not displayed in these articles, making it hard to compare directly.…”

“…In contrast, the electrochemical detection method has received much attention due to its rapidity, simplicity, and low cost. Since caffeine is an electroactive molecule, different electrochemical sensors have been developed for direct oxidation of caffeine, including but not limited to bare glassy carbon, graphene oxide composite, − molecularly imprinted polymer electrodes, , and chemically modified graphite pencil electrodes. , However, to date, the interference signal caused by other diverse electroactive ingredients (e.g., dopamine, catechin, gallic acid, vitamin, etc.) in the real caffeinated food has not been fully addressed and remains challenging. , Although potentially resolved, the obtained redox signals of these interferents were usually large and wide, which easily cover up the trace signal from caffeine.…”

An adsorptive stripping voltammetric study based on disposable pencil graphite sensor for the determination of caffeine in local brand ice tea

“…The U.S. Food and Drugs Administration determined the maximal amount of CAF in soft drinks was approximately lower than 200 mg/L and specified the lethal dose only 10 g of CAF (about 170 mg/kg body weight) per people [11]. Since high concentration levels of CAF are toxic for human beings, it can lead to depression, hyperactivity, nausea and nervousness, heart diseases, kidney failure, asthma, vomiting, trembling, seizures, and DNA modification effects [12][13][14][15]. Therefore, developing a fast, sensitive, selective, and reliable method for analyzing CAF is an essential role in human health.…”