Abstract:

A new method using a microcolumn packed with nanometer TiO2 as solidphase extractant was developed for the preconcentration and separation of trace amounts of Te(Ⅳ) prior to its measurement by ultraviolet spectrophotometry. Effects of pH, sample flow rate and volume, elution solution and coexisted ions on the recovery of the analytes were investigated. The sorption was optimized with respect to the pH, the maximum sorption was achieved from the solution of pH 8~9.5, and the adsorption percentage was 99%. Sorbed Te(Ⅳ) was desorbed in 2.0 mL of 0.5 mol/L NaOH, with an enrichment factor of 30. The detection limit(3σ) of the method for Te(Ⅳ) was 0.013 mg/L(n=13); and the relative standard deviation was 1.99%(n=13, c=30 mg/L). At room temperature, the dynamic saturated adsorption capacity was 37.02 mg/g. The proposed method was applied to the determination of trace amounts of Te(Ⅳ) in water samples, the determined values were in good agreement with the certified values.

Key words: flow injection, microcolumn preconcentration, titanium dioxide, tellurim