Extraction-spectrophotometric determination of iron with 2-[2-(3,5-dibromopyridyl)azo]-5-dimethylaminobenzoic acid

Abstract

An extraction-spectrophotometric method for the determination of trace amounts of iron based on its extraction into chloroform with 2-[2-(3,5-dibromopyridyl)azo]-5-dimethylaminobenzoic acid from a weakly acidic medium has been developed. The maximum absorbance of the extracted species occurs at 615 nm. The reagent was very sensitive and reacted with iron(II) to form a stable, blue 1 : 2 (Fe : reagent) complex, which was extracted into chloroform. The apparent molar absorptivitiy of the iron(II) complex was 9.36 × 10⁴ l mol^–1 cm^–1 at 615 nm in chloroform. The method has been applied to the determination of iron in various samples, such as aluminium alloys, silicon carbide powders and well waters.