Abstract:

A method using a microcolumn packed with nanometer TiO2 as solid-phase extractant has been developed for the preconcentration of trace amounts of Se(Ⅳ) prior to the measurement by ultraviolet spectrophotometry. Effects of pH, sample flow rate and volume, elution solution and interfering ions on the recovery of the analytes have been investigated. The sorption was optimized with respect to the pH, maximum sorption was achieved from the solutions of pH 1~ 6. The optimum sample flow rate to adsorb Se(Ⅳ) ions was 0.5 mL/min, and the adsorption percentage was 98.3%. Sorbed Se(Ⅳ) was desorbed with 1.0 mL of 0.1 mol/L NaOH, with an enirchment of 40. The detection limit(3σ) of the method for Se(Ⅳ) was 0.13 mg/L(n=13); and the relative standard deviation was 1.56%(n=13, c=10 mg/L). At room temperature, dynamic saturated adsorption capacity was 7.92 mg/g. The proposed method was applied to the determination of trace amounts of Se(Ⅳ) in GBW07280, the determined value was in good agreement with the certified value.

Key words: heterogemini surfactant CmOhpNC8,NaBr,aqueous solution surface tension,premicellization