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Advisor(s)
Abstract(s)
Os poluentes emergentes são substâncias potencialmente tóxicas que, embora encontradas em baixas concentrações, da ordem dos mg.L-1 ou inferior, podem produzir efeitos nocivos no meio ambiente. Devido às suas concentrações vestigiais, ainda não estão, na sua grande maioria, incluídos nos programas de controlo da qualidade da água nem nas regulamentações nacionais ou internacionais de controlo ambiental. Os Produtos Farmacêuticos e de Cuidados Pessoais (Pharmaceutical and Personal Care Products - PPCPs) representam um importante grupo de poluentes emergentes devido ao aumento do consumo mundial e à capacidade inerente de induzirem efeitos fisiológicos nocivos em doses muito baixas, o que suscita várias preocupações relacionadas com os possíveis efeitos adversos em humanos, animais e sistemas ambientais. O objetivo primeiro deste trabalho é identificar os principais poluentes emergentes em meios hídricos, de meios populacionais com características semelhantes às do distrito de Bragança e selecionar alguns para estudo. Pretende-se também desenvolver e implementar experimentalmente um método expedito de extração em fase sólida (SPE) para compostos pertencentes a classes farmacológicas diferentes e sua posterior deteção e quantificação em matrizes aquosas usando cromatografia líquida acoplada com um detetor de arranjo de díodos (HPLC-DAD). O método a desenvolver deve ser aplicável a fármacos de classes diferentes e com um valor de pKa elevado. A validação do método de extração e de quantificação será realizada através da sua implementação em amostras reais, como por exemplo, amostras fluviais, de piscinas ou estações de tratamento de águas residuais, entre outras.
Inicialmente foram selecionados para estudo dez fármacos (azitromicina, sulfametoxazol, carbamazepina, diclofenaco, naproxeno, ibuprofeno, ácido acetilsalicílico, cafeína, paracetamol e cetoprofeno), que foram divididos em dois grupos. No primeiro grupo foram colocados compostos com um valor de pKa mais baixo e no segundo grupo os compostos com um valor de pKa mais elevado. Esta subdivisão baseia-se no diferente comportamento ácido-base destes dois grupos com a consequente necessidade de realizar otimizações diferentes para as fases móveis utilizadas em cromatografia líquida. Para o grupo de compostos com um valor de pKa menor utilizou-se uma coluna Nucleosil® C18, compatível com valores de pH compreendidos entre 2 e 8. Para o grupo de compostos com pKa mais elevado, utilizou-se uma coluna SiliaChrom® XT C18 compatível com uma gama de pH entre 1 e 12. A otimização do método de separação e quantificação foi realizada em diferentes etapas. Na primeira etapa, estudou-se a influência da composição do solvente na resolução cromatográfica de cada grupo de fármacos. Utilizaram-se, nesta primeira etapa, diferentes misturas entre acetonitrilo:água:modificador ácido (ácido trifluoroacético) e diferentes misturas entre metanol:água:modificador básico (dietilamina). De seguida, estudaram-se vários tipos de gradientes de solvente de forma a melhorar o tempo de análise da separação cromatográfica. Nesta otimização, selecionaram-se os comprimentos de onda para cada composto, de forma a maximizar o valor de absorvância, de modo a otimizar-se também os limites de deteção e quantificação do método cromatográfico.
Após a otimização de todo o processo de extração, separação e quantificação por SPE/HPLC-DAD, o método foi validado com a análise de oito amostras reais recolhidas em diferentes matrizes aquosas: Rio Sabor, Rio Onor, Rio Fervença, Piscina Municipal, Rio Sousa, um Ribeiro, água de torneira da rede de distribuição municipal, e água recolhida à saída da ETAR. Constatou-se que apenas a água à saída da ETAR estava contaminada com uma substância não identificada.
Emerging pollutants are potentially toxic substances that, although found in low concentrations, in the order of mg/L or lower, can produce harmful effects on the environment. Due to their trace concentrations, they are for the most part not yet included in water quality control programs or national or international environmental control regulations. Pharmaceutical and Personal Care Products (PPCPs) represent an important group of emerging pollutants due to increasing world consumption and the inherent ability to induce harmful physiological effects at very low doses, which raises several concerns related to possible adverse effects on humans, animals and environmental systems. The first objective of this work is to identify the main emerging pollutants in water from populations with similar characteristics to those of Bragança district and select some for study. It is also intended to experimentally develop and implement an expedited method of solid phase extraction (SPE) for compounds belonging to different pharmacological classes and their subsequent detection and quantification by liquid chromatography coupled with an array diode array detector (HPLC-DAD) in aqueous matrices. The method to be developed should be applicable to pharmaceutical drugs of different classes and with a high pKa value. The validation of the extraction and quantification method will be performed through its implementation in real samples, such as swimming pool samples, river samples or wastewater treatment plants, among others. Initially, ten drugs were selected for study (azithromycin, sulfamethoxazole, carbamazepine, diclofenac, naproxen, ibuprofen, acetylsalicylic acid, caffeine, paracetamol and ketoprofen) which were divided into two groups. Compounds with a lower pKa value were placed in the first group and compounds with a higher pKa value in the second group. This subdivision is based on the different acid-base behaviour of these two groups with the consequent need to perform different optimizations for the mobile phases used in liquid chromatography. For the group of compounds with a lower pKa a Nucleosil® C18 column compatible with pH values between 2 and 8 was used. For the group of compounds with a higher pKa a SiliaChrom® XT C18 column compatible with pH range between 1 and 12 was used. The optimization of the separation and quantification method was performed in different steps. In the first stage, the influence of solvent composition on the chromatographic resolution of each drug group was studied. Different mixtures between acetonitrile: water: acid modifier (trifluoroacetic acid) and different mixtures between methanol: water: basic modifier (diethylamine) were used in this first step. Then, various types of solvent gradients were studied in order to improve the time of chromatographic separation analysis. In this optimization, the wavelengths for each compound were selected in order to maximize the absorbance value, in order to optimize the detection and quantification limits of the chromatographic method. After optimization of the entire extraction, separation and quantification process by SPE / HPLC-DAD, the method was validated by analysing eight real samples collected in different aqueous matrices: Sabor river, Onor river, Fervença river, Municipal Pool, Sousa river, a brook, tap water from the municipal distribution network, and water collected outside the City Waste Water Treatment Plant (WWTP). Only water leaving the WWTP was found to be contaminated with a non-identified substance.
Emerging pollutants are potentially toxic substances that, although found in low concentrations, in the order of mg/L or lower, can produce harmful effects on the environment. Due to their trace concentrations, they are for the most part not yet included in water quality control programs or national or international environmental control regulations. Pharmaceutical and Personal Care Products (PPCPs) represent an important group of emerging pollutants due to increasing world consumption and the inherent ability to induce harmful physiological effects at very low doses, which raises several concerns related to possible adverse effects on humans, animals and environmental systems. The first objective of this work is to identify the main emerging pollutants in water from populations with similar characteristics to those of Bragança district and select some for study. It is also intended to experimentally develop and implement an expedited method of solid phase extraction (SPE) for compounds belonging to different pharmacological classes and their subsequent detection and quantification by liquid chromatography coupled with an array diode array detector (HPLC-DAD) in aqueous matrices. The method to be developed should be applicable to pharmaceutical drugs of different classes and with a high pKa value. The validation of the extraction and quantification method will be performed through its implementation in real samples, such as swimming pool samples, river samples or wastewater treatment plants, among others. Initially, ten drugs were selected for study (azithromycin, sulfamethoxazole, carbamazepine, diclofenac, naproxen, ibuprofen, acetylsalicylic acid, caffeine, paracetamol and ketoprofen) which were divided into two groups. Compounds with a lower pKa value were placed in the first group and compounds with a higher pKa value in the second group. This subdivision is based on the different acid-base behaviour of these two groups with the consequent need to perform different optimizations for the mobile phases used in liquid chromatography. For the group of compounds with a lower pKa a Nucleosil® C18 column compatible with pH values between 2 and 8 was used. For the group of compounds with a higher pKa a SiliaChrom® XT C18 column compatible with pH range between 1 and 12 was used. The optimization of the separation and quantification method was performed in different steps. In the first stage, the influence of solvent composition on the chromatographic resolution of each drug group was studied. Different mixtures between acetonitrile: water: acid modifier (trifluoroacetic acid) and different mixtures between methanol: water: basic modifier (diethylamine) were used in this first step. Then, various types of solvent gradients were studied in order to improve the time of chromatographic separation analysis. In this optimization, the wavelengths for each compound were selected in order to maximize the absorbance value, in order to optimize the detection and quantification limits of the chromatographic method. After optimization of the entire extraction, separation and quantification process by SPE / HPLC-DAD, the method was validated by analysing eight real samples collected in different aqueous matrices: Sabor river, Onor river, Fervença river, Municipal Pool, Sousa river, a brook, tap water from the municipal distribution network, and water collected outside the City Waste Water Treatment Plant (WWTP). Only water leaving the WWTP was found to be contaminated with a non-identified substance.
Description
Keywords
Poluentes emergentes Compostos farmacêuticos Ambiente Extração em fase sólida