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Advisor(s)
Abstract(s)
Nos últimos anos, produtos farmacêuticos como antibióticos tornaram-se importantes contaminantes ambientais devido ao seu uso massivo e à sua persistência. As estações de tratamento de águas residuais (ETARs) convencionais não são eficientes na sua eliminação. Por este motivo, estes são amplamente distribuídos no ambiente e, embora sejam encontrados em concentrações muito reduzidas, a sua presença associouse a danos à saúde humana e animal. Neste contexto fica claro a grande importância da análise de contaminantes, não só para avaliar a qualidade do ambiente, mas também para conhecer fontes de contaminantes e a sua distribuição. Os métodos mais comuns para a análise ambiental (e.g. a cromatografia) requerem instrumentação cara e complexa. Devido a mobilidade e distribuição dos contaminantes no ambiente é de elevada importância desenvolver ferramentas portáteis que permitam a sua análise de maneira rápida e in situ, para assim obter informação em tempo real. Deste modo, no presente trabalho procurou-se desenvolver uma plataforma eletroanalítica miniaturizada e portátil baseada em papel para a deteção de azitromicina, que é um antibiótico amplamente prescrito para o tratamento de infeções respiratórios. O uso do papel como substrato permitiu pré-concentrar o analito (azitromicina) na própria plataforma antes de realizar a medição, melhorando a sensibilidade do método. Depois de otimizadas as condições de pré-concentração, verificou-se que esta préconcentração permitiu reduzir significativamente o limite de deteção (LOD): de 0,24 mM (medida direta) a 7,2 µM (com pré-concentração). Além disso, comparativamente com elétrodos serigrafados comerciais (SPEs) a plataforma desenvolvida apresentou uma maior sensibilidade e um LOD mais baixo. Por outro lado, o uso do papel também permitiu utilizar a plataforma como armazenamento de amostras, sendo a resposta estável pelo menos até 28 dias. Finalmente, a plataforma desenvolvida foi testada com sucesso para a análise da azitromicina em solventes orgânicos. Deste modo, apresenta-se como um primeiro passo para o desenvolvimento de uma solução viável e verde para a análise rápida e descentralizada de contaminantes no ambiente.
In the last few years, pharmaceuticals such as antibiotics have become important environmental contaminants due to their massive use and their persistence. Conventional wastewater treatment plants are not efficient in their elimination. Subsequently, they are widely distributed in the environment and, although found at very low concentrations, their presence has been associated with damage on human and animal health. In this context, the importance of pollutant analysis is clear, not only to assess the quality of the environment, but also to understand the sources of pollutants and their distribution. The most common methods for environmental analysis (e.g. chromatography) require complex instrumentation and long analysis times. Due to the mobility and distribution of pollutants in the environment, it is very important to develop portable tools that allow rapid and in situ analysis of pollutants in order to obtain real time information. Thus, in the present work the development of a paper-based, miniaturized analytical platform was pursued for the detection of azithromycin, which is an antibiotic widely prescribed for the treatment of respiratory tract infections. The use of paper as a substrate allowed the analyte (azithromycin) to be pre-concentrated on the platform itself before making the measurement in order to improve the sensitivity of the method. After optimizing the preconcentration conditions, it was found that this preconcentration significantly reduced the detection limit (LOD): from 0.24 mM (direct measurement) to 7.2 µM (with preconcentration). In addition, compared to commercial screen-printed electrodes (SPEs), the developed platform also presented a higher sensitivity and lower LOD. On the other hand, the use of paper also allowed the storage of samples; the response was stable for at least 28 days. Finally, the developed platform was successfully tested for azithromycin analysis in organic solvents. It is, therefore, a first step towards the development of a viable and green solution for rapid and decentralized analysis of contaminants in the environment.
In the last few years, pharmaceuticals such as antibiotics have become important environmental contaminants due to their massive use and their persistence. Conventional wastewater treatment plants are not efficient in their elimination. Subsequently, they are widely distributed in the environment and, although found at very low concentrations, their presence has been associated with damage on human and animal health. In this context, the importance of pollutant analysis is clear, not only to assess the quality of the environment, but also to understand the sources of pollutants and their distribution. The most common methods for environmental analysis (e.g. chromatography) require complex instrumentation and long analysis times. Due to the mobility and distribution of pollutants in the environment, it is very important to develop portable tools that allow rapid and in situ analysis of pollutants in order to obtain real time information. Thus, in the present work the development of a paper-based, miniaturized analytical platform was pursued for the detection of azithromycin, which is an antibiotic widely prescribed for the treatment of respiratory tract infections. The use of paper as a substrate allowed the analyte (azithromycin) to be pre-concentrated on the platform itself before making the measurement in order to improve the sensitivity of the method. After optimizing the preconcentration conditions, it was found that this preconcentration significantly reduced the detection limit (LOD): from 0.24 mM (direct measurement) to 7.2 µM (with preconcentration). In addition, compared to commercial screen-printed electrodes (SPEs), the developed platform also presented a higher sensitivity and lower LOD. On the other hand, the use of paper also allowed the storage of samples; the response was stable for at least 28 days. Finally, the developed platform was successfully tested for azithromycin analysis in organic solvents. It is, therefore, a first step towards the development of a viable and green solution for rapid and decentralized analysis of contaminants in the environment.
Description
Keywords
Análise eletroquímica Dispositivos baseados em papel Pré- -concentração Azitromicina Contaminantes Electroanalysis Paper-based devices Preconcentration Azithromycin Contaminants