Abstract

Solid phase extraction of gold using nano-ZnO sorbent prior to its flame atomic absorption spectrometric determination

Author(s): Zahra Monsef Khoshhesab, Yasmin Khavarian

A solid phase extraction procedure is presented for the separation and preconcentration of trace levels of Au (III) ions by using nano-ZnO. The experimental parameters such as sample pH, sorbent mass, contact time, sample volume, eluent volume, type of eluent, and interference of some ions on adsorption and recovery of Au(III) were investigated using batch procedure. The maximum adsorption capacity of the sorbent for Au(III) was found to be 584 mg g –1. The sorption ofAu (III) was quantitative in the pH range of 3.5-4.5 and quantitative desorption occurred with 5.0 mL of Na2S2O3 and KSCN(1.0mol L-1). In the initial solution, the calibration curve was linear in the range of 1.3 - 200 µgL-1ofAu(III) (r = 0.9994), the detection limit (3õ b, n = 8)was 0.39 µg L–1, relative standard deviation (R.S.D) of 15 µg L–1 ofAu(III) was 1.9 % (n = 8), and the preconcentration factor was 100. The proposed method has been successfully applied to separation and determination of gold(III) ions in water samples.