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Please use this identifier to cite or link to this item: http://repositorio.ufba.br/ri/handle/ri/5085

Title: Spectrophotometric determination of chromium in steel with 4-(2- thiazolylazo)-resorcinol (TAR) using microwave radiation
Other Titles: Journal of the Brazilian Chemical Society
Authors: Carvalho, Luciene Santos de
Costa, Antonio Celso Spinola
Ferreira, Sergio Luis Costa
Teixeira, Leonardo Sena Gomes
Keywords: chromium;TAR;spectrophotometric;microwave radiation;steel
Issue Date: Jan-2004
Publisher: Sociedade Brasileira de Química
Abstract: A spectrophometric method for the determination of Cr(III) with 4-(2- thiazolylazo)-resorcinol was developed. Cr(III) slowly forms a red complex with TAR at pH 5.7. Irradiating the reacting mixture with microwave energy can accelerate the complex formation. The absorbance reached its maximum with 5 min of irradiation and remained stable, at least, for 24 h. N-cetyl-N,N,N-trimethylammonium bromide (CTAB) was used for increasing the sensitivity and solubility of the system. The method allowed the determination of chromium ranging from 0.050 to 3.0 mg mL-1 (9.62 x 10-7 to 5.77 x 10-5 mol L-1) with a molar absorptivity of 2.73x104 L-1 mol-1 cm-1 and a detection limit of 17 ng mL-1 (3.3 x 10-7 mol L-1) at 545 nm. The selectivity was improved by using EDTA and citrate as masking agents. Fe(III) interferes and must be extracted previously, if present in the sample. The proposed method has been successfully applied to the determination of chromium in steel. The precision (R.S.D. < 2%) and accuracy were satisfactory.
Description: p.153-157
URI: http://www.repositorio.ufba.br/ri/handle/ri/5085
ISSN: 0103-5053
Appears in Collections:Artigos Publicados em Periódicos (Quimica)

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