Determinação e fracionamento de bário em castanha-do- Pará

Detalhes bibliográficos
Ano de defesa: 2007
Autor(a) principal: Gonçalves, Alexandra Mary
Orientador(a): Nóbrega, Joaquim de Araújo lattes
Banca de defesa: Não Informado pela instituição
Tipo de documento: Dissertação
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal de São Carlos
Programa de Pós-Graduação: Programa de Pós-Graduação em Química - PPGQ
Departamento: Não Informado pela instituição
País: BR
Palavras-chave em Português:
Área do conhecimento CNPq:
Link de acesso: https://repositorio.ufscar.br/handle/20.500.14289/6403
Resumo: In this work it was studied the determination and fractionation of barium in Brazil nuts employing several strategies for sample preparation and spectroanalytical techniques, i.e. graphite furnace atomic absorption spectrometry (GFAAS) and inductively coupled plasma optical emission spectrometry with axial view (ICP OES). Brazil nuts is a widely consummed food due to its nutritional value and good taste. The chemical analysis of Brazil nuts is not trivial due to its complex matrix. The fractionation of barium in Brazil nuts was studied owing to the toxicity of this element and the strong correlation between chemical form and absorption. The total content of barium varied from 860 to 2084 mg/kg. Sequential extractions were performed based on solubility in different media and also lipids, proteins and low molecular weight fractions (LMW). Barium was determined in all extracts by ICP OES. The highest contents of barium were determined in the LMW and insoluble fractions with 778 to 1606 and 551 to 1520 mg/kg, respectively. As expected, these results indicate the unavailability of this element in this food for humans. Based on the contents of barium and sulfur in different fractions and stoichiometric calculations it was possible to infer that barium occurs in the BaSO4 form. The presence of this chemical form was also confirmed by thermogravimetric experiments.