Simultaneous determination of copper and iron in automotive gasoline by X-ray fluorescence after pre-concentration on cellulose paper |
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Authors: | Leonardo S.G. Teixeira,Rodrigo B.S. Rocha,Paulo R.B. Guimarã es,Josanaide S.R. Teixeira |
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Affiliation: | a Departamento de Engenharia e Arquitetura, Universidade Salvador-UNIFACS, Av. Cardeal da Silva 132, 40.220-141 Salvador-BA, Brazil b Centro Federal de Educação Tecnológica da Bahia (CEFET-BA), Rua Emídio dos Santos S/N, 40301-015 Salvador-BA, Brazil |
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Abstract: | This paper proposes an alternative analytical method using energy dispersive X-ray fluorescence (EDXRF) to determine Fe and Cu in gasoline samples. In the proposed procedure, samples were distilled and the distillation residues were spotted on cellulose paper disk to form a uniform thin film and to produce a homogeneous and reproducible interface to the XRF instrument. The disks were dried at 60 °C for 20 min and copper and iron were determined directly in the solid phase at 6.40 and 8.04 keV, respectively. The calibration curves showed linear response in the 20-800 μg L−1 concentration range of each metal. The precisions (repeatability) calculated from 15 consecutive measurements and defined as the coefficient of variation of solutions containing 100 μg L−1 of Fe and Cu were 7.8 and 8.1%, respectively. The limits of detection (LOD), defined as the analyte concentration that gives a response equivalent to three times the standard deviation of the blank (n = 10), were found to be 10 and 15 μg L−1 for Fe and Cu, respectively. The proposed method was applied to copper and iron determination in gasoline samples collected from different gas stations. |
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Keywords: | Gasoline EDXRF Metals Iron Copper |
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