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Expansão do portfólio de análise de compostos inorgânicos através do desenvolvimento da análise de elementos químicos em efluentes gasosos
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Abstract(s)
A presente dissertação foi desenvolvida no âmbito do estágio curricular realizado na Eurofins Lab Environment Testing Portugal e teve como principal objetivo a validação de dois métodos distintos para a determinação de metais em efluentes gasosos: um para a quantificação de Antimónio (Sb), Arsénio (As), Cádmio (Cd), Cobalto (Co), Cobre (Cu), Crómio (Cr), Chumbo (Pb), Manganês (Mn), Níquel (Ni), Tálio (T) e Vanádio (V) por Espetrometria de Massa com Plasma Indutivamente Acoplado (ICP-MS), e outro para a determinação de Mercúrio (Hg) por
Espetrometria de Absorção Atómica por Vapor Frio (CV-AAS). Ambos os métodos recorreram à digestão assistida por micro-ondas como técnica de preparação de amostras. Para avaliar o desempenho dos métodos em diferentes matrizes, foram realizados ensaios representativos de quatro tipos de amostras de efluentes gasosos: filtros de fibra de quartzo de 47 mm, soluções de lavagem, soluções de absorção de 150 mL e de 500 mL.
No método ICP-MS foram aplicadas as normas EN 14385:2024 e EN 14793:2017, tendo sido otimizadas as condições instrumentais (RF POWER, sample depth, caudal do nebulizador e de hélio, velocidade da bomba do nebulizador) e selecionados os isótopos adequados para os analitos e para os elementos do padrão interno. A validação do método permanece como trabalho futuro, embora já tenham sido estabelecidas gamas de trabalho e explorada a hipótese de desenvolver curvas de calibração sem a necessidade de digestão dos respetivos padrões. Apesar da otimização das condições instrumentais, não foi possível concluir a validação durante
o período de estágio, mantendo-se o método numa fase preliminar. O método CV-AAS demonstrou excelente desempenho analítico, evidenciado pela excelente linearidade das curvas de calibração (coeficiente de correlação de 0,9999), pelas taxas médias de recuperação dentro do intervalo de 80-120%, e pela exatidão comprovada através da análise do material de referência certificado (BCR-038). Para cada tipo de amostra, os ensaios
evidenciaram que os limites de quantificação foram inferiores aos exigidos pela Portaria n.◦190-B/2018, Decreto-Lei n.◦39/2018 e Decreto-Lei n.◦127/2013, e que os limites de deteção, bem como os parâmetros de repetibilidade e reprodutibilidade, ficaram abaixo dos valores exigidos pela norma EN 13211:2001. A única limitação observada foi a gama de trabalho obtida ([0,05-1,00] μg/L), inferior à recomendada pela mesma norma. Concluiu-se que o método CV-AAS apresenta elevado potencial para a determinação de Hg em emissões gasosas, sendo necessária a demonstração de equivalência com a norma de referência para a sua implementação definitiva.
This dissertation was developed as part of the curricular internship carried out at Eurofins Lab Environment Testing Portugal and aimed to validate two distinct analytical methods for the determination of metals in gaseous effluents: one for the quantification of antimony (Sb), arsenic (As), cadmium (Cd), cobalt (Co), copper (Cu), chromium (Cr), lead (Pb), manganese (Mn), nickel (Ni), thallium (Tl), and vanadium (V) using Inductively Coupled Plasma Mass Spectrometry (ICP-MS), and another for the determination of mercury (Hg) using Cold Vapor Atomic Absorption Spectrometry (CV-AAS). Both methods employed microwave-assisted digestion as the sample preparation technique. To assess method performance across different matrices, representative tests were conducted on four types of gaseous effluent samples: 47 mm quartz fiber filters, rinsing solutions, and absorption solutions of 150 mL and 500 mL. For the ICP-MS method, standards EN 14385:2024 and EN 14793:2017 were applied, with optimization of instrumental conditions (RF POWER, sample depth, nebulizer and helium flow rates, and nebulizer pump speed) and selection of appropriate isotopes for both analytes and internal standards. Method validation remains as future work, although working ranges have already been established and the possibility of developing calibration curves without the need for digestion of the respective standards has been explored. Despite the optimization of instrumental conditions, it was not possible to complete the validation during the internship period, and the method remains in a preliminary phase. The CV-AAS method demonstrated excellent analytical performance, as evidenced by the outstanding linearity of the calibration curves (correlation coefficient of 0,9999), average recovery rates within the 80-120% range, and accuracy confirmed using certified reference material (BCR-038). For each sample type, the tests showed that the quantification limits complied with the requirements set out in Portuguese legislation (Portaria n.◦190-B/2018, Decreto-Lei n.◦39/2018, and Decreto-Lei n.◦127/2013), and that detection limits, repeatability, and reproducibility parameters were below the thresholds established by EN 13211:2001. The only limitation observed was the working range obtained ([0,05-1,00] μg/L), which was lower than that recommended by the same standard. It was concluded that the CV-AAS method shows strong potential for the determination of Hg in gaseous emissions, although demonstration of equivalence with the reference standard is required for its definitive implementation.
This dissertation was developed as part of the curricular internship carried out at Eurofins Lab Environment Testing Portugal and aimed to validate two distinct analytical methods for the determination of metals in gaseous effluents: one for the quantification of antimony (Sb), arsenic (As), cadmium (Cd), cobalt (Co), copper (Cu), chromium (Cr), lead (Pb), manganese (Mn), nickel (Ni), thallium (Tl), and vanadium (V) using Inductively Coupled Plasma Mass Spectrometry (ICP-MS), and another for the determination of mercury (Hg) using Cold Vapor Atomic Absorption Spectrometry (CV-AAS). Both methods employed microwave-assisted digestion as the sample preparation technique. To assess method performance across different matrices, representative tests were conducted on four types of gaseous effluent samples: 47 mm quartz fiber filters, rinsing solutions, and absorption solutions of 150 mL and 500 mL. For the ICP-MS method, standards EN 14385:2024 and EN 14793:2017 were applied, with optimization of instrumental conditions (RF POWER, sample depth, nebulizer and helium flow rates, and nebulizer pump speed) and selection of appropriate isotopes for both analytes and internal standards. Method validation remains as future work, although working ranges have already been established and the possibility of developing calibration curves without the need for digestion of the respective standards has been explored. Despite the optimization of instrumental conditions, it was not possible to complete the validation during the internship period, and the method remains in a preliminary phase. The CV-AAS method demonstrated excellent analytical performance, as evidenced by the outstanding linearity of the calibration curves (correlation coefficient of 0,9999), average recovery rates within the 80-120% range, and accuracy confirmed using certified reference material (BCR-038). For each sample type, the tests showed that the quantification limits complied with the requirements set out in Portuguese legislation (Portaria n.◦190-B/2018, Decreto-Lei n.◦39/2018, and Decreto-Lei n.◦127/2013), and that detection limits, repeatability, and reproducibility parameters were below the thresholds established by EN 13211:2001. The only limitation observed was the working range obtained ([0,05-1,00] μg/L), which was lower than that recommended by the same standard. It was concluded that the CV-AAS method shows strong potential for the determination of Hg in gaseous emissions, although demonstration of equivalence with the reference standard is required for its definitive implementation.
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Keywords
CV-AAS microwave digestion ICP-MS mercury metals validation Digestão por micro-ondas Mercúrio Metais Validação