On-line preconcentration and determination of Au(Ⅲ) in various environmental/industrial samples by flame atomic absorption spectrometry

摘要

A rapid and simple on-line method is described for the determination of Au(Ⅲ) in various samples. The method is based on the sorption of gold(Ⅲ) on Lewatit MonoPlus TP207 chelating resin including the iminodiacetate group, which is used as sorbent material and packed in a minicolumn. The chemical variables such as the pH of the sample solution, eluent type, interfering ions and concentrations of reagents, and instrumental variables such as sample loading volume, reagents flow rates, and tubing length, which affect the efficiency of the method were studied and optimised. Au(Ⅲ) was sorbed on the chelating resin, from which it could be eluted with 3 mol L~(-1) HCl, and then introduced directly to the nebuliser-bumer system of FAAS. The limit of detection of the method was 0.2 μg L~(-1) while the relative standard deviation was ＜4.0% for 20 μg L~(-1) Au(Ⅲ) concentration. The preconcentration factor was found to be 106 while the optimised sample volume was 15.3 mL. The accuracy of the method was verified by analysing the certified reference material. The developed method was applied successfully for the determination of gold in different samples with satisfactory results.