Percorrer por autor "Oliveira, Ana Teresa Lopes Branco de"
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- Extração e quantificação de fármacos em matrizes aquosasPublication . Oliveira, Ana Teresa Lopes Branco de; Queiroz, Ana; Ribeiro, António E.; Brito, PauloOs 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.
- Extraction and quantification of pharmaceutical drugs in aqueous matricesPublication . Oliveira, Ana Teresa Lopes Branco de; Nemoto, Ana; Ribeiro, António E.; Queiroz, Ana; Brito, PauloThe increasing production and use of chemical compounds, coupled with inefficient sewage treatment systems, results in an inadequate release of all types of pollutants into the environment. Emerging pollutants are potentially toxic substances normally found in very small concentrations but that can produce harmful effects on the environment. These compounds are not yet included in water quality monitoring programs nor in environmental control legislation standards. Pharmaceutical and Personal Care Products (PPCPs) are an important group of emerging pollutants due to their continuing increase in world consumption and their inherent capacity to induce physiological effects at very low doses, raising concerns about potential adverse effects in humans, animals and environmental systems.
- Fármacos como poluentes emergentes em meios aquosos no Nordeste de PortugalPublication . Oliveira, Ana Teresa Lopes Branco de; Ribeiro, António E.; Queiroz, Ana; Brito, PauloPharmaceutical drugs have been considered as one of the priority pollutants belonging to emerging contaminants regarding environmental pollution. Their presence in aqueous matrices is related with emissions in their production, direct disposal in environment and human and/or animal excretion. These micropollutants can be found in rivers and other aqueous matrices, in concentrations below the ppm level. Nowadays, there is a strong interest in developing inexpensive and optimized determination methods for these compounds. This presentation presents the development of a complete analytical methodology and its validation, for the detection and quantification of a set of eight different pharmaceutical drugs belonging to different therapeutic classes: azithromycin, sulfamethoxazole, caffeine, paracetamol, acetylsalicylic acid, ketoprofen, diclofenac, and carbamazepine. The selected method was SPE/HPLC-DAD because it is a more economically attractive method and easier to implement. Experimental results will include solid phase extraction (SPE) as an extraction/concentration technique followed by detection and quantification using high performance liquid chromatography with a diode array detector (HPLC-DAD). The complete separation of all the eight studied compounds requires the use of two different chromatographic columns and the optimization of two mobile phase compositions. For compounds with low pKa values a Nucleosil 100-5 C18 column is used with a acetonitrile:water:trifuoracetic acid solvent composition. For compounds with higher pKa values, a SiliaChrom XT C18 column is used with a methanol:water:diethylamine solvent composition. SPE recoveries, calibration curves, limits of detection and quantification will be presented. Several samples were collected from three different rivers from the Bragança region and the developed methodology was implemented to measure drugs concentration.
- Monitoring of non-steroidal anti-inflammatory drugs in hydric media from the Bragança regionPublication . Nemoto, Ana; Oliveira, Ana Teresa Lopes Branco de; Queiroz, Ana; Brito, Paulo; Ribeiro, António E.Emerging micropollutants are substances found in the environment in very low concentrations, at scales ranging from nanograms to micrograms per liter. Usually, wastewater treatment plants are not designed with the purpose of removing these pollutants. Non-steroidal anti-inflammatory drugs (NSAIDs) are some of the most prescribed drugs worldwide in order to relief pain and inflammatory conditions. Several studies report the presence of these pharmaceuticals in different aqueous matrices. Therefore, in this work will be presented an extensive set of experimental results obtained for the development and validation of a complete methodology used to identify and quantify five selected NSAIDs (acetylsalicylic acid, diclofenac, ibuprofen, ketoprofen and naproxen) in samples collected from different hydric media of the Bragança region, northern Portugal. Experimental results includes the optimization of solid phase extraction (SPE) and high performance liquid chromatography with diode array detector (HPLC-DAD) operating conditions, namely, SPE recoveries, HPLC mobile phase composition and pH based on different acetonitrile/water/trifluoroacetic acid contents under isocratic or gradient modes, and optimum wavelengths to improve limits of detection and quantification, among others. The SPE extraction is performed using Chromabond® HLB cartridges, and the optimized extraction process resulted in mass recovery values between 86.5% and 99.3%. After SPE extraction the samples were analyzed by HPLC-DAD using a C18 column, a 60%acetonitrile:40%water:0.01%trifluoroacetic acid solvent composition and a flow-rate of 1.2 mL/min. The selected wavelengths were 219 nm for ibuprofen, 224 nm for acetylsalicylic acid and naproxen, 254 nm for ketoprofen and 275 nm for diclofenac. The experimental methodology was validated using real samples from different aqueous matrices collected in the Bragança region.
- Monitoring of non-steroidal anti-inflammatory drugs in hydric media from the Bragança regionPublication . Nemoto, Ana; Oliveira, Ana Teresa Lopes Branco de; Queiroz, Ana; Brito, Paulo; Ribeiro, António E.Emerging micropollutants are chemical substances present in different matrices at very low concentrations, ranging from nanograms to micrograms per liter. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are some of the most prescribed drugs worldwide and several studies report the presence of these substances in various hydric media including drinking water, surface water, sewage water, among others1. Since they are present in very low concentrations, their identification, quantification and removal are not easy tasks2.
- Pharmaceutical drugs as emerging pollutants in aqueous media of Northeast PortugalPublication . Oliveira, Ana Teresa Lopes Branco de; Ribeiro, António E.; Brito, Paulo; Queiroz, AnaEmerging pollutants are potentially toxic substances that although found in very small concentrations can produce hazard effects to the environment. Due to their very small concentrations they are not yet included in the water quality monitoring programs neither in national or international environmental control regulations. Pharmaceutical and Personal Care Products (PPCPs) represent an important group of emerging pollutants owing to increased worldwide consumption and to their inherent capacity to induce physiological harmful effects in very low doses, which raises several concerns related with the potential adverse effects on humans, animals and environmental systems. In this work, it will be presented the development and validation of a complete experimental methodology proposed for the monitoring of pharmaceutical drugs. The method is based on solid phase extraction (SPE) followed by analysis with high performance liquid chromatography with a diode array detector (HPLC-DAD). Experimental results obtained with two different columns will be presented. An analytical Nucleosil 100-5 C18 column, 150 mm x 4.6 mm, obtained from Macherey-Nagel for compounds with lower pKa values and a SiliaChrom XT C18 column, 4.6 mm x 250 mm, obtained from SiliCycle for compounds with higher pKa values. The method is validated by the analysis of real aqueous matrices samples obtained from different water media sources, such as, swimming pools, rivers and wastewater treatment plants. To extend the scope of the analytical method and thus obtain a broader study, several drugs were selected, belonging to five different pharmacological classes: non-steroidal anti-inflammatory (ibuprofen, acetylsalicylic acid, ketoprofen, naproxen and diclofenac), analgesic (paracetamol), antibiotic (sulfamethoxazole), an anticonvulsant (carbamazepine) and a central nervous system stimulator (caffeine). These compounds were selected due to their high level of use and medical prescription and, consequently, leading to a high probability of environmental contamination.
- Pharmaceutical drugs as environmental emerging pollutantsPublication . Oliveira, Ana Teresa Lopes Branco de; Ribeiro, António E.; Brito, Paulo; Queiroz, AnaPharmaceutical drugs have been considered in recent years as one of the groups belonging to emerging contaminants regarding environmental pollution. Their presence in aqueous matrices is mainly related to emissions in their production, direct disposal in environment and human and/or animal excretion. These pollutants can be found in rivers and other aqueous matrices, in very low concentrations, below the ppm level. As, normally, they occur in trace concentrations, their identification and quantification were complex tasks since they require very expensive and not so available analytical methods. Additionally, the actual European Legislation is still scarce for this called “emergent contaminants”. Nowadays, there is a strong interest in the development of inexpensive and acute determination methods for these compounds, to overcome the huge lack of information about the potential harmful effects in the living beings and in the environment. In this study, it will be presented the development of a complete analytical methodology and its validation, for the detection and quantification of a set of eight different pharmaceutical drugs. The studied pharmaceutical drugs, azithromycin, sulfamethoxazole, caffeine, paracetamol, acetylsalicylic acid, ketoprofen, diclofenac, and carbamazepine, are representative drugs of several different therapeutic classes: two antibiotics, one central nervous system stimulant, two analgesics, two non-steroidal anti-inflammatories and one anticonvulsant, respectively. Experimental results will include solid phase extraction (SPE) as an extraction/concentration technique followed by detection and quantification using high performance liquid chromatography with diode array detector (HPLC-DAD). The complete separation of all the studied compounds requires the use of two different columns and the optimization of two mobile phase compositions. For compounds with low pKa values a Nucleosil 100-5 C18 column is used with a solvent composed of acetonitrile:water:trifuoracetic acid. For compounds with higher pKa values a SiliaChrom XT C18 column is used with a methanol:water:diethylamine solvent composition. SPE recoveries, calibration curves, limits of detection and quantification will be presented. Several samples were collected from three different rivers from the Bragança region and the developed methodology was implemented to measure drugs concentration.
- Rapid determination of some of the most used pesticides in Northeast Portugal as emerging contaminants in rivers by SPME/GC-MSPublication . Oliveira, Ana Teresa Lopes Branco de; Hmida, Raed Ben; Ribeiro, António E.; Brito, Paulo; Queiroz, AnaIn this communication the development of an analytical methodology is presented for the monitoring of five emerging pollutants, namely, alachlor, metolachlor, heptachlor, dimethoate, and terbuthylazine. These compounds are among the most used pesticides in the northeast region of Portugal and Tunisia. The complete experimental methodology is optimized based on the simultaneous extraction and concentration of all five pesticides from aqueous matrices, by means of solid-phase micro-extraction (SPME) followed by detection and quantification using gas chromatography with mass spectrometry (GC-MS). The optimization of the extraction step is performed using a polydimethylsiloxane-divinylbenzene (PDMS-DVB) coated SPME fiber by direct immersion (DI-SPME) in the aqueous sample. Experimental conditions, such as extraction temperature and time, pH value, salt addition, and desorption time and temperature in the GC injector port were studied. The optimum value for each one of these parameters was selected based on the maximum total area value obtained in MS detector, using Full Scan Mode, for the mixture of five pesticides. The extraction optimized conditions were achieved by immersion of a PDMS-DVB fiber in the sample mixture with 10% NaCl, a pH value of 2, at 60 °C for 80 min. Desorption of the compounds from the fiber is done in the GC port at 250 °C during 4 min. The Shimadzu GC-MS equipment, model QP2020, operating conditions were also studied, and the main separation and detection parameters were selected. Samples were analyzed using a Rxi-5MS Low Bleed capillary column from Restek and the following oven temperature program: initial temperature of 120 °C (held for 2 min), increased by 15 °C.min-1 to 190 °C (held for 4 min) and, finally, increased by 10 °C.min-1 to 227 °C and held for 1 min. The MS instrument operating in the Electron Ionization mode (EI) was used for a full scan. The acquisition was performed in the range of 35–450 (m/z). The ion source temperature was 200 °C and the interface temperature was 270 °C. The identification and quantification were carried out using calibration curves obtained from the extraction of a standard mixture of the five selected pesticides for at least six concentration levels, in the same experimental conditions used for the real samples. Detection limits ranged from 4.2 to 6.6 ng/mL. For pesticides with low values of KOW, like dimethoate, the use of a fiber of relatively non-polar nature would be more favourable. The developed experimental methodology was implemented by the analysis of different samples collected from the surface water of three rivers from Bragança, namely, Fervença, Sabor and Onor. All three rivers showed different types and levels of contamination.
- Rapid determination of some of the most used pesticides in Northeast Portugal as emerging contaminants in rivers by SPME/GC-MSPublication . Oliveira, Ana Teresa Lopes Branco de; Hmida, Raed Ben; Ribeiro, António E.; Brito, Paulo; Queiroz, AnaIn this communication the development of an analytical methodology is presented for the monitoring of five emerging pollutants, namely, alachlor, metolachlor, heptachlor, dimethoate, and terbuthylazine. These compounds are among the most used pesticides in the northeast region of Portugal and Tunisia. The complete experimental methodology is optimized based on the simultaneous extraction and concentration of all five pesticides from aqueous matrices, by means of solid-phase micro-extraction (SPME) followed by detection and quantification using gas chromatography with mass spectrometry (GC-MS). The optimization of the extraction step is performed using a polydimethylsiloxane-divinylbenzene (PDMS-DVB) coated SPME fiber by direct immersion (DI-SPME) in the aqueous sample.