A Novel Catalytic Procedure for the Determination of Ultratrace Zirconium

 A novel catalytic procedure for zirconium was proposed based on Zr(IV) catalyzed oxidation of gallocyanine by hydrogen peroxide in hexamethylene tetramine-hydrochloric acid buffer medium. The calibration graph is linear for 0–110 ngċml⁻¹, and the detection limit is 0.4 ngċml⁻¹ Zr(IV). Most foreign ions do not interfere with the determination, except for Cu²⁺, Fe³⁺ and Cr(VI). The interferences of Cu²⁺ and Fe³⁺ could be eliminated by masking with EDTA and mannitol, and that of Cr(VI) by reducing to Cr(III) with ascorbic acid. The typical features of this procedure are that it is sensitive for zirconium, and the determination could be carried out at room temperature. It had been used to the determination of zirconium in zirconium bronze, simulated samples and a certified reference material. The recoveries were 98.6 ∼ 102%, and relative standard deviations (R.S.D.) were 0.9 ∼ 1.5%, respectively. Received September 12, 1999. Revision April 10, 2000.