Abstract
A colorimetric determination of copper by extraction with carbon tetrachloride solution of zinc diethyldithiocarbamate has been investigated. This method gave a coloration in the presence of iron (III), cobalt, nickel, and bismuth but their disturbances were far less than when sodium diethyldithiocarbamate was used and showed to be a superior method on account of its simplicity. The following method was found to be good for avoiding the disturbing influences of these ions. Namely, the copper is extracted with carbon tetrachloride solution of dithizone, and the carbon tetrachloride layer is extracted with an aqueous solution of zinc bis (hydroxyethyl) dithiocarbamate for quantitative moving of the copper into the aqueous layer. The aqueous layer is then extracted with carbon tetrachloride of zinc diethyldithiocarbamate and the transmittance of the carbon tetrachloride layer is estimated. This method gives an accurate quantitative determination of copper in the presence of 1000 times as much of iron, manganese, cobalt, nickel, and silver.
