Colorimetric Determination of Trace Metals in Beer and in Brewing Materials Iv. Determination of Copper

Copper is determined in the residue obtained after wet oxidation of beer or brewing materials as described in a previous paper (this Journal, 1951, 363). When the residue is treated with sodium diethyldithiocarbamate, a compound is formed which is soluble in carbon tetrachloride giving a yellow solution. The yellow colour of this solution may be matched by glass slides in a Lovibond tintometer or evaluated in a photoelectric colorimeter. The copper is determined by reference to standard curves.