3 documents found, page 1 of 1
Determinação de Mn, Cu e Zn em matrizes salinas após separação e pré-concentraç...
Santos Júnior,Aníbal de Freitas; Korn,Maria das Graças Andrade; Jaeger,Helena Valli; Silva,Nívia Maria Silveira; Costa,Antonio Celso SpínolaThe aim of this work was to explore the possibility of the application of a non-ionic resin obtained by impregnation of Alizarin Red S (VAS) in Amberlite XAD-7 for manganese, copper and zinc separation and preconcentration in saline matrices. For these system, the metals were quantitatively retained, in the pH range 8.5-10.0, by using 0.50 g of solid phase, stirring time of five minutes and a total mass up to 2...
Spectrophotometric determination of uranium using 2-(2- Thiazolylazo)-p-Cresol ...
Teixeira,Leonardo Sena Gomes; Costa,Antonio Celso Spínola; Ferreira,Sérgio Luís Costa; Freitas,Maria de Lourdes; Carvalho,Marcelo Souza deA sensitive and selective spectrophotometric method is proposed for the rapid determination of uranium using 2-(2- Thiazolylazo)-p-Cresol (TAC). The reaction between TAC and uranium (VI) is instantaneous at pH 6.5 and the absorbance remains stable for over 3 h. N-cetyl-N,N,N-trimethylamonium bromide (CTAB) and triton X-100 are used for increasing the sensitivity and solubility of the system respectively. The me...
Spectrophotometric Determination of Zinc Using 7-(4-Nitrophenylazo)-8-Hydroxyqu...
Korn,Maria das Graças Andrade; Ferreira,Adriana Costa; Teixeira,Leonardo Sena Gomes; Costa,Antonio Celso SpínolaA sensitive and selective spectrophotometric method is proposed for the rapid determination of zinc(II) using an 8-hydroxyquinoline derivative, 7-(4-nitrophenylazo)-8-hydroxyquinoline-5-sulfonic acid (p-NIAZOXS), as a new spectrophotometric reagent. The reaction between the p-NIAZOXS and zinc(II) is instantaneous at pH 9.2 (borax buffer) and the absorbance remains stable for over 24 h. The method allows the det...