Spectrophotometric determination of iron(III) with oxine and zephiramine.

Abstract

Iron reacts with oxine to form a blue-black water-soluble complex in the presence of an excess of zephiramine (tetradecyl-dimethyl-benzyl-ammonium chloride). The complex was stable for at least 4 hours, and had two absorption maxima at 460 mμ and 580 mμ in the range of pH 2.8 to 11. Beer's law held for 14180 μg of iron in 25 ml of the aqueous solution containing 10 ml of 0.5% zephiramine solution and 2 ml of 0.3% oxine solution at pH 33.7.The apparent molar absorptivities at 460 mμ and 580 mμ were 4.7×103 and 3.5×103, respectively. The interference from copper was removed by filtering the precipitate of copper oxinate, and that from titanium by measuring the absorbance at 580 mμ.