Extraction and spectrophotometric determination of iron(III) with N-phenylcinnamohydroxamic acid

Abstract

Iron(III) reacts with N-Phenylcinnamohydroxamic acid to form an orange coloured complex quantitatively extractable into benzene from acidic medium. The complex has an absorption maximum around 440 nm with a molar absorptivity of 8000 l·mol−1·cm−1. The effect of foreign ions and several experimental variables on the extraction of iron(III) have been studied. The composition of the complex has been found to be 1∶3 (metal∶ligand) with an overall stability constant of 6.15×1011. On the basis of these studies a simple, precise, sensitive, and highly selective method has been developed for the extraction and spectrophotometric determination of iron(III). The method has been applied for the successive extraction and spectrophotometric determination of vanadium and iron in BCS steels.