Desenvolvimento de sensores impressos e descartáveis para a detecção de compostos de importância ambiental e biológica

• Autor(a) principal: Andreotti, Isabela Aparecida de Araujo
• Data de Publicação: 2019
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFSCAR
• Texto Completo: https://repositorio.ufscar.br/handle/ufscar/11875
• topic: Tinta condutora; Sensor descartável; Sensor eletroquímico; Hidroquinona; Estriol; Conductive ink; Disposable sensor; Electrochemical sensor; Hydroquinone; CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA ANALITICA::ELETROANALITICA

Disposable electrochemical sensors have attracted the attention of the scientific community given its advantages, such as large-scale production with relatively low cost and reduced sample volume. In this context, the technique of printed electrodes has been widely used in electroanalytical for the development of new sensing platforms and in the improvement of their performances. With the objective of developing disposable sensors with low relative cost, through the printing technique, two conductive inks were developed: one from nail polish (NP) for nails and graphite (GP) and another paint from stained glass varnish (GV) and graphite. As a substrate of the sensor, we used PET from bottles of drinks that would be discarded. After the development of the conductive ink, the morphological and electrochemical characterization of GP-NP / PET and GP-GV / PET devices were performed. To verify the functionality of the sensors, hydroquinone (HQ), serotonin (5-HT), epinephrine (EP) and estriol (E3) were chosen as analytes. The scanning electron microscopy characterization of GP-NP / PET and GP-GV / PET revealed that the inks have a homogeneous, rough and porous surface, characteristics that help increase the surface area of the working electrode. Using the square-wave voltammetry technique, the GP-NP / PET sensor presented a linear response in the concentration range of 5.0 × 10−6 to 1.0 × 10−4 mol L−1 with a detection limit of 1.2 × 10−8 mol L−1 for HQ, 5,0 × 10−5 to 1,0 × 10−4 mol L−1 with a detection limit of 3,1 × 10−7 mol L−1 for 5-HT and 1.0 × 10−7 to 5.0 × 10−5 mol L−1 with a detection limit of 1 × 10−7 mol L−1 for EP. For the GP-GV/PET device, 1.0 × 10−7 at 8.0 × 10−6 mol L−1 to was obtained with a detection limit of 1 × 10−8 mol L−1 for E3. The devices detected the analytes in environmental, pharmaceutical and biological samples. In this way, the inks developed are interesting for the application in disposable sensors, given their characteristics as homogeneity while liquid, and physical stability after drying, not breaking, following the flexibility of the substrate.