https://repositorio.ufba.br/handle/ri/5058
metadata.dc.type: | Artigo de Periódico |
Título : | Application of Box–Behnken design in the optimisation of an on-line pre-concentration system using knotted reactor for cadmium determination by flame atomic absorption spectrometry |
Otros títulos : | Spectrochimica Acta Part B: Atomic Spectroscopy |
Autor : | Souza, Anderson Santos Santos, Walter Nei Lopes dos Ferreira, Sergio Luis Costa |
metadata.dc.creator: | Souza, Anderson Santos Santos, Walter Nei Lopes dos Ferreira, Sergio Luis Costa |
Resumen : | The present paper proposes an on-line pre-concentration system for cadmium determination in drinking water using flame atomic absorption spectrometry (FAAS). Cadmium(II) ions are retained as 1-(2-pyridylazo)-2-naphthol (PAN) complex at the walls of a knotted reactor, followed of elution using hydrochloric acid solution. The optimization was performed in two steps using factorial design for preliminary evaluation and a Box–Behnken design for determination of the critical experimental conditions. The variables involved were: sampling flow-rate, reagent concentration, pH and buffer concentration, and as response the analytical signal (absorbance). The validation process was performed considering the parameters: linearity and other characteristics of the calibration curve, analytical features of on-line pre-concentration system, precision, effect of other ions in the pre-concentration system and accuracy. Using the optimized experimental conditions, the procedure allows cadmium determination with a detection limit (3 j/ S) of 0.10 Ag Lÿ1, a quantification limit (10 j/ S) of 0.33 Ag Lÿ1, and a precision, calculated as relative standard deviation (RSD) of 2.7% (n =7) and 2.4% (n =7) for cadmium concentrations of 5 and 25 Ag Lÿ1, respectively. A pre-concentration factor of 18 and a sampling frequency of 48 hÿ1 were obtained. The recovery for cadmium in the presence of several ions demonstrated that this procedure could be applied for the analysis of water samples. The method was applied for cadmium determination in drinking water samples collected in Salvador City, Brazil. The cadmium concentrations found in five samples were lower than the maximum permissible levels established by the World Health Organization. |
Palabras clave : | Multivariate optimisation Cadmium Knotted reactor On-line preconcentration Cd Optimization Knotted-reactor Flame AAS |
URI : | http://www.repositorio.ufba.br/ri/handle/ri/5058 |
Fecha de publicación : | 2005 |
Aparece en las colecciones: | Artigo Publicado em Periódico (Química) |
Fichero | Descripción | Tamaño | Formato | |
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0-S0584854705000224-main.pdf | 126,26 kB | Adobe PDF | Visualizar/Abrir |
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