Development of a system for estrogen detection in complex matrices. Establishing an e-tongue for estrogen detection and developing a tool for data analysis

• Autor(a) principal: Reis, Tiago Ferreira Félix da Costa
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/155440
• topic: Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Eletrotécnica, Eletrónica e Informática

The development of sensors that detect molecules as Emerging Pollutants (EPs), at low con-centration in aqueous complex solutions, is important to improve the quality of aquifers and water bodies. In this work such a sensor was developed to detect 10-16M of estrogen on tap water. To achieve such a sensor, the electronic tongue (e-tongue) system was used. An e-tongue consists of an array of sensorial devices connected to a microprocessor capable of predicting concentrations based on the readings. Each sensor is prepared with indigitated elec-trodes with or without thin films deposited on them. Three thin films are studied in this work the PEI/GO, PEI/mwcnt and PAH/PAZO, each with five bilayers. To collect data from each of the sensorial devices, an impedance spectroscopy was used on different concentrations of estro-gen. To analyze the data collected from the sensorial devices, a PCA is used to create a three-dimensional plane using PC1, PC2, and −log10(). Then a SVM is used to find the optimal values for the hyperplane with the calibration. For the collected data with the three sensorial devices, the sensibilities for PC1 and PC2 were 0.418 and −0.186 respectively, with an intercept of −14.5. Managing the raw data from the sensors is a "big data" problem, and the ETDA tool was developed to facilitate the extraction of relevant features as well as creating and calibrating the PCA for the sensors array. ETDA stands for Electronic Tongue Data Analytics, and as the name suggests, it is meant to assist with the development of any e-tongue system, valuing them. As it is, ETDA can, for each experiment, plot the impedance spectroscopy from Solartron 1260, as well as the relevant features over the concentrations for the frequencies with the highest variations.