In this work, we present evidence about the best complexation pH of the [Fe (o-fen) 3 ] 2+ complex . The literature cites that this complex is quantitative from pH = 2.0 to 9.0. We verified that at pH = 9,2 the complex has the highest absorbance, demonstrating that this is the most complex pH. It is concluded that the ideal pH for Fe (II) conversion with o-phenanthroline, when this complex is free of interferents, is 9.2.
