Emprego da microextração líquido-líquido dispersiva para extração de ferro em cerveja e determinação por espectrometria de absorção atômica com chama

• Ano de defesa: 2023
• Autor(a) principal: Seco, Maiuca Alberto
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Santa Maria; Brasil; Química; UFSM; Programa de Pós-Graduação em Química; Centro de Ciências Naturais e Exatas
• Palavras-chave em Português: DLLME; Ferro; Cerveja; Preparo de amostra; FAAS; Iron; Beer; Sample preparation; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA
• Link de acesso: http://repositorio.ufsm.br/handle/1/31723

In this work, a sample preparation method based on dispersive liquid-liquid microextraction (DLLME) for the extraction and preconcentration of Fe in beer and subsequent determination by flame atomic absorption spectrometry (F AAS) was developed. Although DLLME recommends the use of an extracting solvent and a dispersing solvent, in this work only the extracting solvent was used. For Fe extraction by DLLME, the type and volume of extracting solvent, sample volume, concentration and type of complexant, pH effect, effect of salt addition, and the influence of the number of washing steps after extraction were evaluated. After optimization of DLLME, 75 μL of 1,2-dichlorobenzene (C6H4Cl2) as extracting solvent, 10 mL of beer (without any dilution) as sample volume, 500 μL of 0.5% (w/v) ammonium pyrrolidinedithiocarbamate (APDC) as complexing agent were selected, without the need for pH adjustment, salt addition and washing steps after extraction. After optimization of the DLLME conditions, an external calibration curve was carried out, from which a determination coefficient better than 0.99 was obtained. The proposed DLLME/F AAS method was applied for Fe determination in three beer samples and the results were compared with those obtained after microwave assisted decomposition (MAD) and determination by inductively coupled plasma optical emission spectrometry (ICP-OES). The Fe concentration in the 3 samples ranged from 59.7 to 68.2 μg L-1 and from 54.4 to 57.2 μg L-1 for DLLME/F AAS and MAD/ICP-OES, respectively. The proposed method for Fe extraction and preconcentration presented suitable precision and accuracy and can be used in routine analysis for Fe determination in beer and similar matrices.