Extraction spectrophotometric determination of iron(III) with 2-hydroxy-1-naphthaldehyde oxime

Abstract

A selective extraction-spectrophotometric method is proposed for the determination of microgram amounts of iron. The method is based on the formation of an insoluble iron(III)-2-hydroxy-1-naphthaldehyde oxime complex, which is extractable into chloroform from an aqueous solution at pH 3.5. The iron(III)-2-hydroxy-1-naphthaldehyde oxime complex in chloroform exhibits an absorption maximum at 580 nm with a molar absorptivity of 6.4 × 103 l mol–1 cm–1. The complex system conforms to Beer's law for up to 8 p.p.m. of iron(III). The method is simple in that a single extraction suffices; common ions, except molybdenum(VI) and titanium(IV), do not interfere in the determination. The method has been applied successfully to the analysis of non-ferrous alloys.