About 1mg. of phenylmercuric acetate in aqueous acid solution of pH 2-2.5, is titrated with 1.5×10-4M carbon tetrachloride solution of copper diethyldithiocarba-mate as the standard solution, the end point being slight tinting of the carbon tetrachloride layer to yellowish brown. Mean rate of determination error is less than -0.5% and assumed value of standard deviation is 0.5%.
