A new, simple, rapid, sensitive, efficient and low-cost spectrophotometric procedure for the determination of gold was developed. The method is based on the reaction of [AuCl4]-with 2-[2-(4-dimethylaminophenyl)- vinyl]-1,3,3-trimethyl-3H-indolium reagent to form a colored ion associate extractable by various organic solvents. The molar absorptivity of the ion associates is in the range (5.7-9.2) × 104 L mol-1 cm-1 depending on the extractant. Butyl acetate was chosen as the extractant. The optimum reaction conditions were established: pH 2-4, concentration of the dye reagent (0.8-1.5)- 10-4 mol L-1. The determination of gold is not hindered even by a 1000-fold concentration of Ni and Co; a 500-fold concentration of Pb and Zn; a 100-fold concentration of Bi, Cu, Cd, Pt, Rh and Ru; or a 20-fold concentration of Ag. The established method was applied to the determination of gold in model samples and enriched polymetallic ores.
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