[Determination of trace gold by flame atomic absorption spectrometry after separation and preconcentration with load nanometer titanium dioxide].

A new method for the determination of trace gold by flame atomic absorption spectrometry (FAAS) after preconcentration with p-dimethylaminobenzylidenerhodanine (DMABR) loaded with nanometer TiO2 was developed. The method is convenient, highly precise and linear in a wide range. Under dynamic condition, the optimum pH of solution, flow rate, elution conditions were obtained for preconcentration of trace gold. And the effect of interfering ions was also investigated. It was found that the studied gold could be quantitatively preconcentrated on loaded nanometer TiO2 at pH = 3.5, and the flow rate of sample solution was 0.6 mL x min(-1), and the flow rate of eluting solution with 0.1 mol x L(-1) HCl-0.5 mol x L(-1) thiourea was 0.5 mL x min(-1), sufficient for complete elution. The dynamic adsorption capacity of gold on load nanometer TiO2 was 23.19 mg x g(-1). The linear range for gold was 0-0.40 microg x mL(-1), correlation coefficient was 0. 999 3, detection limit (3sigma, n = 11) for gold was 2.34 ng x mL(-1), and the relative standard deviation was 2.9% (n = 6, c = 0.10 microg x mL(-1)), the recovery was in the range of 96.7%-101.7%. The method has been applied to the determination of trace gold in water samples with satisfactory results.