Abstract
2- (5-Nitro-2-pyridylazo) -5- (N-propyl-N-sulfopropylamino) phenol (nitro-PAPS) reacts with iron(II), copper and zinc, but not with iron(III). The iron(II) complex is formed at pH 3.49 and has an absorption maximun at 582 nm. Copper forms a 1: 1 complex at pH 2.54.5 and a 1: 2 complex at pH 89. Zinc reacts at pH 89. The absorption maxima of copper and zinc complexes are at 565 nm. When sodium periodate was added to a sample solution containing copper, iron and zinc at pH 3.5, only the copper complex was formed. Accordingly, only copper could be determied. On the other hand, the sum content of iron and copper was determined in the presence of ascorbic acid at pH 3.5. Also, the total contents of iron, copper and zinc were determined at pH 8.5. Three metal ions in the range of 0.020.5μg ml-1 could be determined individually and the proposed method is useful for determinations in sera.
