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Uso do violeta de alizarina N (AVN) como reagente espectrofotométrico na determ...
Dantas,Alailson Falcão; Costa,Antônio Celso Spínola; Ferreira,Sérgio Luís CostaThe present work proposes the application of the 4-Hidroxy-3-(2-hydroxynaphtylazo)-benzenesulphonic acid (C.I. 15670), Alizarine Violet N (AVN), as a reagent for direct aluminium determination using molecular absorption spectrophotometry in the presence of tensoatives. Al(III) cation reacts with AVN in pH 9.4, forming a red complex, stable for at least 24 hours, with absorption minimum at 607nm and, against a r...
Uso de irradiação de microondas na determinação espectrofotométrica de cromo co...
Costa,Antônio Celso Spínola; Assis,Júlio César Rosa; Torres,André Luís Carvalho; Ferreira,Sérgio Luís Costa; Korn,Maria das Graças AndradeCr(III) slowly forms a violet complex with EDTA at pH 2.5-5.0 under normal conditions. The complex formation can be accelerated by irradiating the reacting mixture with microwave energy. The complex Cr(III)-EDTA is completely formed within 3 minutes of microwave irradiation and followed by a simple and rapid method for spectrophotometric determination of chromium. The method may be successfully applied to deter...
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...