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Please use this identifier to cite or link to this item: http://repositorio.ufba.br/ri/handle/ri/14064

Title: Application of Doehlert designs for optimisation of an on-line preconcentration system for copper determination by flame atomic absorption spectrometry
Other Titles: Talanta
Authors: Ferreira, Sergio Luis Costa
Bezerra, Marcos de Almeida
Santos, Walter Nei Lopes dos
Barros Neto, Benício de
Keywords: Doehlert designs;Copper;Flame atomic absorption spectrometry
Issue Date: 2003
Abstract: In the present paper, a system for on-line preconcentration and determination of copper by flame atomic absorption spectrometry (FAAS) was developed. It was based on solid phase extraction of copper(II) ions on a minicolumn of Amberlite XAD-2 loaded with 2-(2-thiazolylazo)-5-dimethylaminophenol (TAM). The optimisation process was carried out using Doehlert designs. Four variables (sampling flow rate, SR; elution flow rate, buffer concentration, BC; and pH) were regarded as factors in the optimisation. The parameter “sensitivity efficiency (SE)” proposed in this paper, and defined as the analytical signal obtained for an on-line enrichment system for a preconcentration time of 1 min was used as analytical response in the optimisation process. Using the established experimental conditions, the proposed on-line system allowed determination of copper with detection limit (3σ/S) of 0.23 μg l−1, and a precision (repeatability), calculated as relative standard deviation (R.S.D.) of 3.9 and 3.7% for copper concentration of 5.00 and 20.00 μg l−1, respectively. The preconcentration factor obtained is 62. The recovery achieved for copper determination in presence of several cations demonstrated that this has enough selectivity for analysis of food samples. The robustness of the proposed system was also evaluated. The accuracy was confirmed by analysis of the following certified reference materials (CRMs): Rice flour NIES 10a, Spinach leaves NIST 1570a, Apples leaves NIST 1515 and Orchard leaves NBS 1571. This procedure was applied for copper determination in natural food samples.
Description: Texto completo: acesso restrito. p. 295–303
URI: http://repositorio.ufba.br/ri/handle/ri/14064
ISSN: 0039-9140
Appears in Collections:Artigos Publicados em Periódicos (Quimica)

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