A carregar...
Publicação
Avaliação detalhada da incerteza de medição de contaminantes e nutrientes no meio marinho
| Nome: | Descrição: | Tamanho: | Formato: | |
|---|---|---|---|---|
| 3.51 MB | Adobe PDF |
Autores
Resumo(s)
A proteção e preservação do ambiente marinho é fundamental para o desenvolvimento social e económico da sociedade. Os oceanos são essenciais para o futuro da humanidade exercendo um papel de extrema importância no ciclo da água e no sistema climático, além de ser uma fonte essencial de biodiversidade e de outros recursos para o planeta. O Instituto Hidrográfico (IH), órgão da Marinha Portuguesa, tem por missão contribuir para o desenvolvimento do País nas áreas científica e de defesa do ambiente marinho. Os Laboratórios de Química e Poluição do Meio Marinho do IH (IH-LQPM) conduzem a sua atividade efetuando
estudos de monitorização da qualidade do meio marinho, desenvolvendo e implementando as metodologias analíticas apropriadas para a caracterização dos diferentes compartimentos. Estes laboratórios são acreditados pelo Instituto Português de Acreditação para a realização de vários ensaios. Mais recentemente, atuam como Instituto Designado de Metrologia representado as mais altas capacidades metrológicas do país para a medição de vários contaminantes e outros parâmetros do meio marinho. Esta atribuição requer a produção de medições da mais alta qualidade metrológica que envolve avaliações “bottom-up” da incerteza de medição. Com o objetivo de desenvolver modelos detalhados da incerteza da medição de mercúrio total em
sedimentos, por espetrometria atómica, e nutrientes em águas, por espetrometria de absorção molecular com fluxo segmentado, foi necessário um levantamento cuidado de todas as fontes de incerteza. A quantificação e combinação destas fontes de incerteza foi realizada recorrendo a uma folha de cálculo, amiga do utilizador, desenvolvida neste trabalho. A ferramenta desenvolvida permite avaliar automaticamente a qualidade dos calibradores, a homogeneidade de variâncias dos sinais, através dos testes de Levene e de Fisher, a linearidade da resposta instrumental, através dos testes ANOVA-LOF e Qui-Quadrado, os limiares analíticos e, por fim, avalia a incerteza de medição. Esta avaliação recorreu à combinação de componentes de incerteza pelo Método Monte Carlo e pela lei de propagação de incertezas, recorrendo a regressões lineares ou quadráticas dos sinais instrumentais. A compatibilidade metrológica entre valores estimados e de referência de
materiais de referência foi usada para avaliar a qualidade dos modelos de incerteza. A incerteza quantificada relevou-se menor que valores máximos admissíveis definidos para testes de aptidão QUASIMEME. A folha de cálculo desenvolvida poderá ser aplicada a outras medições.
The protection and preservation of the marine environment is fundamental for the social and economic development of society. The oceans are essential for the future of humanity, playing an extremely important role in the water cycle and the climate system, in addition to being an essential source of biodiversity and other resources for the planet. The Hydrographic Institute (IH), an organ of the Portuguese Navy, has the mission of contributing to the development of the country in the scientific and defense areas of the marine environment. The IH Marine Chemical and Pollution Laboratories (IH-LQPM) conduct their activity by carrying out studies to monitor the quality of the marine environment, developing and implementing the appropriate analytical methodologies for the characterization of the different compartments. These laboratories are accredited by the Portuguese Accreditation Institute for carrying out several tests. More recently, they act as Designated Institute of Metrology representing the highest metrological capabilities in the country for the measurement of several contaminants and other parameters of the marine environment. This assignment requires the production of measurements of the highest metrological quality that involve “bottom-up” assessments of measurement uncertainty. In order to develop detailed uncertainty models of measurement of total mercury in sediments, by atomic spectrometry, and nutrients in water, by segmented flow molecular absorption spectrometry, a careful survey of all sources of uncertainty was necessary. The quantification and combination of these sources of uncertainty was performed using a user-friendly spreadsheet developed in this work. The developed tool allows to automatically evaluate the quality of the calibrators, the homogeneity of variances of the signals, through the Levene and Fisher tests, the linearity of the instrumental response, through the ANOVA-LOF and Chi-Square tests, the analytical limits and, for last, it evaluates the measurement uncertainty. This evaluation resorted the combination of uncertainty components by the Monte Carlo Method and the uncertainty propagation law using linear or quadratic regressions of the instrumental signals. Metrological compatibility between estimated and reference values of reference materials was used to assess the quality of uncertainty models. The quantified uncertainty was lower than the maximum admissible values defined by QUASIMEME proeficiency tests. The developed spreadsheet can be applied to other measurements.
The protection and preservation of the marine environment is fundamental for the social and economic development of society. The oceans are essential for the future of humanity, playing an extremely important role in the water cycle and the climate system, in addition to being an essential source of biodiversity and other resources for the planet. The Hydrographic Institute (IH), an organ of the Portuguese Navy, has the mission of contributing to the development of the country in the scientific and defense areas of the marine environment. The IH Marine Chemical and Pollution Laboratories (IH-LQPM) conduct their activity by carrying out studies to monitor the quality of the marine environment, developing and implementing the appropriate analytical methodologies for the characterization of the different compartments. These laboratories are accredited by the Portuguese Accreditation Institute for carrying out several tests. More recently, they act as Designated Institute of Metrology representing the highest metrological capabilities in the country for the measurement of several contaminants and other parameters of the marine environment. This assignment requires the production of measurements of the highest metrological quality that involve “bottom-up” assessments of measurement uncertainty. In order to develop detailed uncertainty models of measurement of total mercury in sediments, by atomic spectrometry, and nutrients in water, by segmented flow molecular absorption spectrometry, a careful survey of all sources of uncertainty was necessary. The quantification and combination of these sources of uncertainty was performed using a user-friendly spreadsheet developed in this work. The developed tool allows to automatically evaluate the quality of the calibrators, the homogeneity of variances of the signals, through the Levene and Fisher tests, the linearity of the instrumental response, through the ANOVA-LOF and Chi-Square tests, the analytical limits and, for last, it evaluates the measurement uncertainty. This evaluation resorted the combination of uncertainty components by the Monte Carlo Method and the uncertainty propagation law using linear or quadratic regressions of the instrumental signals. Metrological compatibility between estimated and reference values of reference materials was used to assess the quality of uncertainty models. The quantified uncertainty was lower than the maximum admissible values defined by QUASIMEME proeficiency tests. The developed spreadsheet can be applied to other measurements.
Descrição
Tese de Mestrado em Química, Faculdade de Ciências, Universidade de Lisboa, 2022
Palavras-chave
Incerteza de medição Método Monte Carlo Nutrientes Analisador de Mercúrio Analisador de fluxo segmentado Teses de mestrado - 2022