Separation and enrichment of gold(Ⅲ) from environmental samples prior to its flame atomic absorption spectrometric determination

摘要

A simple and accurate method was developed for separation and enrichment of trace levels of gold in environmental samples. The method is based on the adsorption of Au(Ⅲ)-diethyldithiocarbarnate complex on Amberlite XAD-2000 resin prior to the analysis of gold by flame atomic absorption spectrometry after elution with 1 mol L~(-1) HNO_3 in acetone. Some parameters including nitric acid concentration, eluent type, matrix ions, sample volume, sample flow rate and adsorption capacity were investigated on the recovery of gold(Ⅲ). The recovery values for gold(Ⅲ) and detection limit of gold were greater than 95% and 16.6 μg L~(-1), respectively. The preconcentration factor was 200. The relative standard deviation of the method was <6%. The adsorption capacity of the resin was 12.3 mg g~(-1). The validation of the presented procedure was checked by the analysis of CRM-SA-C Sandy Soil certified reference material. The presented procedure was applied to the determination of gold in some environmental samples.