Desenvolvimento de eletrodos serigrafados de grafite para a determinação de estrona em água do mar
Data
2024-09-10
Autores
Silva, Caroline Gomes de Andrade 
Orientadores
Simões, Fábio Ruiz
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Os desreguladores endócrinos (DE) são contaminantes emergentes ambientais, que interferem no sistema endócrino de seres humanos e outros animais, existindo estrogênios sintéticos ou naturais, como o hormônio estrona, o principal durante a menopausa, é produzido nos ovários a partir da androstenediona e também através do metabolismo do estradiol. Estudos apontam a presença desses contaminantes em efluentes de estações de tratamento de esgotos (ETEs) em diferentes países. No Brasil, o despejo de esgoto doméstico é a principal razão da poluição nas águas costeiras. O desenvolvimento de sensores como método de monitoramento dos DEs apresenta vantagens como preço reduzido, rapidez, sem o uso de solventes orgânicos, e a possibilidade de monitoramento in situ. Dessa maneira, o presente trabalho teve como objetivo produzir três tipos de eletrodos, SPE, SPE/GO e SPE/rGO para a determinação da estrona. Através da caracterização eletroquímica dos dispositivos por VC constatou-se que os eletrodos modificados com GO e rGO apresentaram aumento da corrente capacitiva, enquanto na EIE causaram redução dos semicírculos no diagrama de Nyquist. Para a determinação da estrona, o único eletrodo que apresentou sinal eletroquímico característico na VC e VPD foi o SPE, sem modificação, dessa forma foi utilizado para as análises eletroanalíticas, sendo construída a curva analítica, pelo método de adição de padrão, permitindo obter um coeficiente de correlação (R2), igual a 0,988 e valores de LOD de 0,234 µmol L-1 e do LOQ de 0,781 µmol L-1. Para a aplicabilidade do método em água do mar foram realizados os testes de recuperação, os resultados encontrados foram de 103,64% e 111,71%, estando dentro dos limites estabelecidos pela ANVISA.
Endocrine disruptors (EDs) are emerging environmental contaminants that interfere with the endocrine system of humans and other animals. They include synthetic or natural estrogens, such as the hormone estrone, which is the primary hormone during menopause and is produced in the ovaries from androstenedione and through the metabolism of estradiol. Studies have detected the presence of these contaminants in effluents from wastewater treatment plants (WWTPs) in various countries. In Brazil, domestic sewage discharge is the main cause of pollution in coastal waters. The development of sensors as a method for monitoring EDs offers advantages such as low cost, speed, the absence of organic solvents, and the possibility of in situ monitoring. Therefore, the present study aimed to produce three types of electrodes SPE, SPE/GO, and SPE/rGO for the determination of estrone. Through the electrochemical characterization of the devices by CV, it was found that the electrodes modified with GO and rGO showed an increase in capacitive current, while in EIS, they reduced the semicircles in the Nyquist diagram. For the determination of estrone, the only electrode that exhibited a characteristic electrochemical signal in CV and DPV was the unmodified SPE, which was then used for electroanalytical analyses. An analytical curve was constructed using the standard addition method, resulting in a correlation coefficient (R²) of 0.988 and LOD and LOQ values of 0.234 µmol L⁻¹ and 0.781 µmol L⁻¹, respectively. For the applicability of the method in seawater, recovery tests were performed, yielding results of 103.64% and 111.71%, within the limits established by ANVISA.
Endocrine disruptors (EDs) are emerging environmental contaminants that interfere with the endocrine system of humans and other animals. They include synthetic or natural estrogens, such as the hormone estrone, which is the primary hormone during menopause and is produced in the ovaries from androstenedione and through the metabolism of estradiol. Studies have detected the presence of these contaminants in effluents from wastewater treatment plants (WWTPs) in various countries. In Brazil, domestic sewage discharge is the main cause of pollution in coastal waters. The development of sensors as a method for monitoring EDs offers advantages such as low cost, speed, the absence of organic solvents, and the possibility of in situ monitoring. Therefore, the present study aimed to produce three types of electrodes SPE, SPE/GO, and SPE/rGO for the determination of estrone. Through the electrochemical characterization of the devices by CV, it was found that the electrodes modified with GO and rGO showed an increase in capacitive current, while in EIS, they reduced the semicircles in the Nyquist diagram. For the determination of estrone, the only electrode that exhibited a characteristic electrochemical signal in CV and DPV was the unmodified SPE, which was then used for electroanalytical analyses. An analytical curve was constructed using the standard addition method, resulting in a correlation coefficient (R²) of 0.988 and LOD and LOQ values of 0.234 µmol L⁻¹ and 0.781 µmol L⁻¹, respectively. For the applicability of the method in seawater, recovery tests were performed, yielding results of 103.64% and 111.71%, within the limits established by ANVISA.
Descrição
Citação
SILVA, Caroline Gomes de Andrade. Desenvolvimento de eletrodos serigrafados de grafite para a determinação de estrona em água do mar. 2024. 54 f. Trabalho de conclusão de curso (Graduação em Engenharia Ambiental) - Universidade Federal de São Paulo, Instituto do Mar, Santos, 2024.