Spectrophotometric Determination of Zirconium with Methylxylenol Blue and Zephiramine

Abstract

Zirconium formed a blue-green complex with Methylxylenol Blue (MXB) in the presence of zephiramine in weakly hydrochloric acid solution, which had an absorption maximum at 627 mμ. Maximum color development of the complex was obtained in the pH range of 1.15-1.35. The calibration curve was linear for 3 -40 μg of zirconium in 25 ml of solution. The molar absorptivity was about 43000 at 627 mμ. The analytical procedure for zirconium was as follows : A sample solution containing 3-40 μg zirconium was taken into 25 ml measuring flask. Suitable amounts of 1N hydrochloric acid, 0.5 ml of 10^-2M zephiramine solution, 2.0 ml of 2% acacia gum solution, and 2.5 ml of 0.1% MXB solution were added to it, and the mixed solution was made up to 25 ml with water (final pH 1.15-1.35). The solution was heated in a water bath of 90±2° for 3 min. After cooling for 7 min, the absorbance of the colored solution was measured at 627 mμ against the reagent blank. Many ions did not interfere with the experiment, but bismuth, thorium, hafnium, and iron (III) interfered even when their amount was the same as that of zirconium. The permissible amount of iron(III) was increased by addition of L-ascorbic acid. The sensitivity of the proposed method is better than that of the previous method.²⁾