https://repositorio.ufba.br/handle/ri/8445
Tipo: | Artigo de Periódico |
Título: | Derivative spectrophotometric determination of nickel using Br-PADAP |
Título(s) alternativo(s): | Talanta |
Autor(es): | Ferreira, Sergio Luis Costa Costa, Antonio Celso Spinola Jesus, Djane S. de |
Autor(es): | Ferreira, Sergio Luis Costa Costa, Antonio Celso Spinola Jesus, Djane S. de |
Abstract: | A major problem with spectrophotometric methods for nickel is cobalt interference, because many of the reagents for nickel also react with cobalt. In this work, the interference of cobalt in the determination of nickel using 2-(5-bromo-2-pyridylaxo)-5-diethylaminophenol (Br-PADAP) was eliminated by the use of derivative spectrophotometry, using the zero-crossing method for evaluation of the derivative signal. Br-PADAP reacts with nickel(II) in the presence of Triton X-100 to form a red complex with absorption maxima at 530 and 562 nm. The reactions parameters and the conditions for the measurements of the first-derivative signal were studied and the results demonstrated that using the derivative technique, Br-PADAP can be used for nickel determination with a selectivity higher than that of ordinary spectrophotometry and with a limit of detection of 0.2 ng ml−1. The pH should be in the range 5.0–6.0 using an acetate buffer. The determination of nickel in the presence of cobalt was performed with conventional and derivative procedures, and the results demonstrated that only the derivative method should be used and, of the methods used for evaluation of the derivative signal, the zero-crossing method is the best. The proposed procedure was used for nickel determination in steels standards. The results demonstrated that the procedure has satisfactory accuracy and precision. Cobalt interference can be also eliminated by using dual-wave-length spectroscopy. |
Palavras-chave: | Br-PADAP Cobalt interference Derivative spectrophotometry Nickel |
URI: | http://www.repositorio.ufba.br/ri/handle/ri/8445 |
Data do documento: | 1996 |
Aparece nas coleções: | Artigo Publicado em Periódico (Química) |
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