Spectrophotometric determination of iron (II) with quinisatin oxime

Abstract

A sensitive spectrophotometric determination of iron is based on the blue color (absorption maximum at 660 mμ) formed by reaction of iron (II) with quinisatin oxime in buffered solution containing ethyl alcohol and a small amount of dimethylformamide. The color develops rapidly and is stable for a few h. The absorbance is well reproducible, and conforms to Beer's law. The optimum concentration range at 1 cm optical path is about 0.5 to 2.5 p.p.m. of iron. Small amounts of iron(III) are reduced by the reagent and cause no difficulty. Cobalt and nickel interfere. Iron(II) and quinisatin oxime react in a 1:3 mole ratio; some possible modes of complex formation are suggested.