This paper describes a method for analyzing gold by atomic absorption. The method involves extracting gold with aqua regia and then analyzing the gold with flame atomic absorption spectrometry.
The document discusses the need for both flame and furnace techniques to analyze gold due to wide variations in content within mineral and ore samples. It highlights that standard acid extraction methods like aqua regia often yield incomplete recovery (90-95%), necessitating more robust separation and analysis strategies.
Various analytical approaches are reviewed, including ion exchange, solvent extraction, chromatography, precipitation, and fire assay methods. The text details specific procedures such as anion exchange resins for silicate ore samples and the use of organic solvents like methyl isobutyl ketone (MIBK) or dibutyl sulphide in toluene for concentrating gold from low-level mineral samples.
The gold recovery is only about 90-95%.
The solvents of choice are methyl isobutyl ketone (MIBK), di-isobuty! ketone (DIBK) and toluene.
Detection limits were as low as 0.2 ng/mL for gold in 1 g of rock sample.