Simple and rapid spectrophotometric determination of trace titanium (IV) enriched by nanometer size zirconium dioxide in natural water

A novel method for preconcentration of Ti(IV) with nanometer size ZrO2 and determination by spectrophotometry has been developed. Ti(IV) was selectively adsorbed on 300 mg ZrO2 from 500 mL solution at pH 6.0, then eluted by 5 mL 11.3 mol L−1 HF. The eluent added was diantipyrylmethane (DAPM, as chromogenic reagent) and ascorbic acid (as masking agent), used for the analysis of Ti(IV) by measuring the absorbance at 390 nm with spectrophotometry, based on the chromogenic reaction between the Ti(IV) and DAPM. This method gave a concentration enhancement of 100 for 500 mL sample, eliminated the sizable interferences on direct determination with spectrophotometry. Detection limit (3σ, n = 11) of 0.1 μg L−1 was obtained. The method was applied to determine the concentration of Ti(IV) in river water and seawater and the analytical recoveries of Ti(IV) added to samples were 97.6-101.3%.