Emprego da microextração líquido-líquido dispersiva em fase reversa como método verde de preparo de amostras de óleo mineral isolante para a determinação de Cu e Fe

• Ano de defesa: 2021
• Autor(a) principal: Wendt, Jéssica Froes de Brito
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Tecnológica Federal do Paraná; Medianeira; Brasil; Programa de Pós-Graduação em Tecnologias Ambientais; UTFPR
• Palavras-chave em Português: Petróleo - Derivados - Análise; Química analítica; Espectrometria de massa; Petroleum products - Analysis; Chemistry, Analytic; Mass spectrometry; CNPQ::ENGENHARIAS::ENGENHARIA SANITARIA; Engenharia/Tecnologia/Gestão
• Link de acesso: http://repositorio.utfpr.edu.br/jspui/handle/1/29716

In this study, a sample preparation method was developed using reversed-phase dispersive liquid-liquid microextraction (RP-DLLME) for the extraction and preconcentration of Cu and Fe in paraffin-based insulating mineral oil samples. The determination of analytes was performed by flame atomic absorption spectrometry (F AAS), using external calibration with aqueous reference solutions. Sample preparation by RP-DLLME was performed with a mixture of extracting and dispersing solvents injected over the sample, then the aqueous phase containing the analytes was separated by centrifugation. Preparation conditions such as type, concentration and volume of extracting solvent, type and volume of dispersing agent, heating temperature, stirring time, centrifugation time and sample mass were adjusted. The limits of quantification (LOQ) for Cu and Fe were 0.0037 and 0.0103 µg g-1, respectively, and the limits of detection (LOD) were 0.0061 µg g-1 for Cu and 0.0020 µg g-1 for Fe. The recovery of analytes ranged from 98 to 104% for Fe, with an RSD below 7%, while for copper the recovery ranged from 98 to 106%, with an RSD below 3%. The proposed method was also applied for the determination of analytes in samples with different stages of use of the insulating mineral oil: new oil, little used, used and burned. A comparison was made between the proposed method and two other reference methods using the metric tool Analytical GREEnness and the AGREE software, in order to characterize the three methods through scores based on the Principles of Green Analytical Chemistry. The method developed was considered adequate for the determination of Cu and Fe in insulating mineral oil samples, and it still has several advantages, such as simplicity of operation, the use of high sample mass, low consumption of reagents, less waste generation, and it has a high analytical frequency. This study is the first application of RP-DLLME in the sample preparation of an insulating mineral oil matrix.