Analytical use of the selective extraction of copper as its phenylacetate

Chloroform solution of phenylacetic add has been found very suitable for extraction and colorimetric determination of copper. Iron and uranium are the main interferences, which can be overcome by masking with ammonium fluoridc. Under these conditions, only gold(III), platinum(IV) and palladium(II) are co-extracted, but their colour does not interfere with measurement of the green copper extract at 700 nm. The method has been applied to the determination of copper in iron, steels, uranium, lead concentrates and alloys containing nickel, cobalt, etc. The extraction procedure can also be used to remove interference of iron, copper and uranium in the determination of manganese with formaldoxime.