Análise de especiação de mercúrio em amostras congeladas de peixes amazônicos e tubarões empregando técnicas cromatográficas e ICP-MS
Data
2023-10-27
Autores
Barros, Matheus de Lima Ribeiro 
Orientadores
Nascimento, Angerson Nogueira do
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
A ingestão de peixes e produtos derivados da pesca estão intimamente relacionados com significativa melhora na saúde e na prevenção de doenças cardiovasculares, visto que estes alimentos são ricos em diversas vitaminas, minerais e ácidos graxos indispensáveis. Entretanto, a crescente poluição de rios e oceanos alteram a qualidade do pescado, já que elementos tóxicos como o mercúrio (Hg) podem ser bioacumulados por diversas espécies, principalmente peixes das regiões amazônicas (devido à intensa exploração garimpeira na região) e tubarões (animais topo de cadeia alimentar que agregam metais pesados de espécies menores que consomem). Neste contexto, o presente estudo objetiva identificar e quantificar espécies moleculares de mercúrio em carnes de tubarão e de peixes amazônicos consumidos no mercado nacional. Realizou-se o procedimento experimental de preparo da amostra empregando processos de liofilização, moagem, digestão total ácida assistida por micro-ondas e análise por ICP-MS, para determinação da concentração total de Hg nos pescados. As amostras in natura de Pirarucu apresentaram concentrações médias de Hg total entre 0,73 ± 0,01 mg/kg e 0,47 ± 0,01 mg/kg, já para as amostras de Cação foi obtido concentrações de 3,29 ± 0,31 mg/kg e 2,38 ± 0,12 mg/kg. Todas as amostras, exceto uma de Pirarucu, apresentaram valores acima dos impostos pela legislação, o que permite concluir que a ingestão dos pescados analisados apresenta risco à saúde humana. Para extração do metilmercúrio, utilizou-se solução extratora de 1% (m/v) L-cisteína·HCl·H2O combinada com agitação e aquecimento da amostra. A melhor condição obtida nas análises cromatográficas foi utilizando solução de 0,1% (m/v) L-cisteína + 0,1% (m/v) L-cisteína·HCl·H2O, no modo isocrático, sendo possível identificar o pico cromatográfico correspondente ao composto, com tempo de retenção próximo de 6 minutos. Os resultados da análise de especiação sugerem que o método proposto não alcançou os critérios exigidos para a quantificação do MeHg.
The consumption of fish and fish-derived products is closely related to a significant improvement in health and the prevention of cardiovascular diseases since these foods are rich in various essential vitamins, minerals, and fatty acids. However, the increasing pollution of rivers and oceans alters the quality of seafood because toxic elements such as mercury (Hg) can be bioaccumulated by various species, especially fish from the Amazon regions (due to intense mining activities in the region) and sharks (animals at the top of the food chain that aggregate heavy metals from smaller species that they consume). In this context, the present study aims to identify and quantify molecular species of mercury in shark and Amazonian fish consumed in the national market. The experimental sample preparation procedure was carried out using processes such as freeze-drying, grinding, microwave-assisted acid digestion, and analysis by ICP-MS to determine the total concentration of Hg in the fish. The in natura samples of Pirarucu showed average Hg total concentrations between 0.73 ± 0.01 mg/kg and 0.47 ± 0.01 mg/kg, while for the Shark samples, concentrations of 3.29 ± 0.31 mg/kg and 2.38 ± 0.12 mg/kg were obtained. All samples, except one from Pirarucu, showed values above those stipulated by the legislation, allowing the conclusion that the consumption of the analyzed fish poses a risk to human health. For the extraction of methylmercury, an extracting solution of 1% (m/v) L-cysteine·HCl·H2O combined with sample agitation and heating was used. The best condition obtained in the chromatographic analyses was using a solution of 0.1% (w/v) L-cysteine + 0.1% (w/v) L-cysteine·HCl·H2O in isocratic mode, allowing the identification of the chromatographic peak corresponding to the compound with a retention time of approximately 6 minutes. The results of the speciation analysis suggest that the proposed method did not meet the required criteria for the quantification of MeHg.
The consumption of fish and fish-derived products is closely related to a significant improvement in health and the prevention of cardiovascular diseases since these foods are rich in various essential vitamins, minerals, and fatty acids. However, the increasing pollution of rivers and oceans alters the quality of seafood because toxic elements such as mercury (Hg) can be bioaccumulated by various species, especially fish from the Amazon regions (due to intense mining activities in the region) and sharks (animals at the top of the food chain that aggregate heavy metals from smaller species that they consume). In this context, the present study aims to identify and quantify molecular species of mercury in shark and Amazonian fish consumed in the national market. The experimental sample preparation procedure was carried out using processes such as freeze-drying, grinding, microwave-assisted acid digestion, and analysis by ICP-MS to determine the total concentration of Hg in the fish. The in natura samples of Pirarucu showed average Hg total concentrations between 0.73 ± 0.01 mg/kg and 0.47 ± 0.01 mg/kg, while for the Shark samples, concentrations of 3.29 ± 0.31 mg/kg and 2.38 ± 0.12 mg/kg were obtained. All samples, except one from Pirarucu, showed values above those stipulated by the legislation, allowing the conclusion that the consumption of the analyzed fish poses a risk to human health. For the extraction of methylmercury, an extracting solution of 1% (m/v) L-cysteine·HCl·H2O combined with sample agitation and heating was used. The best condition obtained in the chromatographic analyses was using a solution of 0.1% (w/v) L-cysteine + 0.1% (w/v) L-cysteine·HCl·H2O in isocratic mode, allowing the identification of the chromatographic peak corresponding to the compound with a retention time of approximately 6 minutes. The results of the speciation analysis suggest that the proposed method did not meet the required criteria for the quantification of MeHg.
Descrição
Citação
BARROS, Matheus de Lima Ribeiro. Análise de especiação de mercúrio em amostras congeladas de peixes amazônicos e tubarões empregando técnicas cromatográficas e ICP-MS. 2023. 83 f. Trabalho de conclusão de curso (Graduação em Química Industrial) - Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, 2023.