Probing the Use of Homemade Carbon Fiber Microsensor for Quantifying Caffeine in Soft Beverages

Autor(es)

Araujo, Karla Caroline de Freitas ; Costa, Emily Cintia Tossi de Araujo ; de Araujo, Danyelle Medeiros ; Santos, Elisama V. ; Martinez-Huitle, Carlos A. ; Castro, Pollyana Souza

• Tipo de documento: Artigo Científico
• Fonte: MATERIALS; v. 16, n. 5, p. 14-pg., 2023-03-01.

Resumo

In the development of electrochemical sensors, carbon micro-structured or micro-materials have been widely used as supports/modifiers to improve the performance of bare electrodes. In the case of carbon fibers (CFs), these carbonaceous materials have received extensive attention and their use has been proposed in a variety of fields. However, to the best of our knowledge, no attempts for electroanalytical determination of caffeine with CF microelectrode (mu E) have been reported in the literature. Therefore, a homemade CF-mu E was fabricated, characterized, and used to determine caffeine in soft beverage samples. From the electrochemical characterization of the CF-mu E in K3Fe(CN)(6) 10 mmol L-1 plus KCl 100 mmol L-1, a radius of about 6 mu m was estimated, registering a sigmoidal voltammetric profile that distinguishes a mu E indicating that the mass-transport conditions were improved. Voltammetric analysis of the electrochemical response of caffeine at the CF-mu E clearly showed that no effects were attained due to the mass transport in solution. Differential pulse voltammetric analysis using the CF-mu E was able to determine the detection sensitivity, concentration range (0.3 to 4.5 mu mol L-1), limit of detection (0.13 mu mol L-1) and linear relationship (I (mu A) = (11.6 +/- 0.09) x 10(-3) [caffeine, mu mol L-1] - (0.37 +/- 0.24) x 10(-3)), aiming at the quantification applicability in concentration quality-control for the beverages industry. When the homemade CF-mu E was used to quantify the caffeine concentration in the soft beverage samples, the values obtained were satisfactory in comparison with the concentrations reported in the literature. Additionally, the concentrations were analytically determined by high-performance liquid chromatography (HPLC). These results show that these electrodes may be an alternative to the development of new and portable reliable analytical tools at low cost with high efficiency. (AU)

• Processo FAPESP: 14/50945-4 - INCT 2014: Instituto Nacional de Tecnologias Alternativas para Detecção, Avaliação Toxicológica e Remoção de Micropoluentes e Radioativos
• Beneficiário: Maria Valnice Boldrin
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 19/13113-4 - Processos foto (eletro) catalíticos e fotoeletro-fenton para eliminar contaminantes emergentes de águas de rejeito industriais
• Beneficiário: Maria Valnice Boldrin
• Modalidade de apoio: Auxílio à Pesquisa - Regular