A modified procedure for the determination of gold with 4,4′-bis(dimethylamino)thiobenzophenone

Abstract

The spectrophotometric determination of gold with 4,4′-bis(dimethylamino)thiobenzophenone has been adapted for routine use in the range 0 to 50 µg of gold.

Composite reagent solutions containing 4,4′-bis(dimethylamino)thiobenzo-phenone, acetic acid, sodium acetate and either ethanol or butanol are convenient and stable, if protected from light.

The reagents give results with 95 per cent. confidence limits of ±1·2 µg (with the ethanolic reagent) and ±1·5 µg (with the butanolic reagent) of gold for a single determination of the absorbance.

Procedures with either reagent are applicable to the determination of up to 50 µg of palladium, silver or mercury.