Simultaneous determination of chromium (III) and copper (II) by using derivative spectrophotometry with MEDTA

The application of derivative spectrophotometry to the simultaneous determination of chromium (III) and copper (II) with MEDTA is described. The procedure is suitable for concentrations of 0.40–2.60 mg ml−1 of chromium (III) and 0.15–0.60 mg ml−1 of copper (II). The main interferences, both anionic and cationic, are easily eliminated. The method was applied to different aqueous matrices. It was compared with an atomic absorption method and good results were obtained.