Um método automático para extração em fase sólida magnética de Cd e Pb em águas e de Cd em óleo comestível e detecção por GF AAS

• Autor(a) principal: Barreto, Inakã Silva
• Data de Publicação: 2016
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFPB
• Texto Completo: https://repositorio.ufpb.br/jspui/handle/tede/9171
• topic: Preparo de amostras on-line; Sistema em fluxo-batelada; Determinação de metais; Extração em fase sólida magnética; Espectrometria de absorção atômica em forno de grafite; Sample preparation on-line; Determination of metals; Magnetic solid phase extraction; Flow-batch system; Graphite furnace atomic absorption spectrometry; CIENCIAS EXATAS E DA TERRA::QUIMICA

In the last decade, the extraction magnetic solid phase (MSPE) has been intense study target in Analytical Chemistry, mainly because of its potential application in sample preparation. Recently, with the development motivation automatic analytical methods, this technique has been combined with flow systems. However, the synergistic integration of MSPE with these systems is still a challenge, especially when it involves the handling of viscous matrices. In this perspective, this thesis proposes the development of an effective automated method to perform the MSPE in aqueous and oily matrices. For be applied as magnetic adsorbent nanoparticles of Fe3O4 coated with alumina and functionalized with sodium dodecyl sulfate (SDS) and 1-(2-pyridylazo)-2-naphthol (PAN) were synthesized. The nanoparticles were characterized by diffraction analysis X-ray and scanning electron microscopy, where it was confirmed that the method used to obtain the particles was adequate. Secondly, the automatic system to run the MSPE was developed. To this end an extraction chamber was made of Teflon with a quartz window on the side, where all steps of MSPE was performed without the need for any auxiliary apparatus for immobilizing the adsorbent. For generating the magnetic field in the extraction chamber, a robotic device has been developed. After these steps, the applicability of the method was demonstrated in the extraction and preconcentration of Cd and Pb in drinking water samples and Cd in edible oils, using as detection atomic absorption spectrometry graphite furnace. Factors affecting MSPE, such as pH, the amount of adsorbent, the type and concentration of the eluent and the elution time were studied. In the best experimental conditions to the sample water, the detection limit was 0.004, and 0.043 ug L-1 for Cd and Pb, respectively. Even in this array, relative standard deviations less than 3.5% were achieved with a 15-fold enrichment factor for both analytes. In the case of determination of Cd in edible oils, detection limit (0.006 ug L-1) and standard deviation (< 3.3%) was obtained satisfactorily with a 9-fold enrichment factor. Interfering studies have been performed successfully for the two determinations, not revealing significant percentage interference in determinations. The developed automatic method is simple and robust since it does not require immobilization of the adsorbent, and was successfully applied in the determination of Cd and Pb in drinking water samples and Cd in edible oils.