QUANTITATIVE DETERMINATION OF GOLD IN SOLUTION BY SOLVENT EXTRACTION AND ATOMIC ABSORPTION SPECTROMETRY

The solvent extraction of gold complex ions into diisobutyl ketone containing either trioctyl methyl ammonium chloride or trioctylamine was investigated. In the rapid determination of gold(III) in aqueous solution the step of extracting gold(III) from an aqueous chloride or cyanide medium into diisobutyl ketone containing the quaternary ammonium salt is recommended. The concentration of the gold in the organic phase may be determined subsequently by atomic absorption spectrometry. The extraction of the gold(III) from an aqueous chloride medium is quantitative at pH values of up to 4, and quantitative extraction of gold(III) from an aqueous cyanide medium is possible at pH values up to at least 10, even when volume ratios of aqueous to organic phases as large as 100:1 are employed. Gold concentrations of between 2.5 X 10-4 to 5 X 10-8M (50 to 0.01 mg/liter) can be determined. This technique has been applied to the analysis of gold-bearing ores and has been found to be free of interference by other elements. Trioctylamine could also be used to extract quantitatively gold(I) cyanide and gold(III) complex ions into diisobutyl ketone, but only under more restricted experimental conditions than those required for the extraction by trioctyl methyl ammonium chloride. © 1969, American Chemical Society. All rights reserved.