The Estimation in Sea-Water Solutions of Micro-Quantities of Mercury in the Presence of Copper by Means of Dithizone

Abstract

1. A brief survey is given of the methods for the estimation of mercury by means of dithizone.2. The precautions necessary in mercury estimations are outlined and the stability of dithizone in chloroform solutions shown to be satisfactory.3. Data are presented on the rate of extraction of copper, from sea-water solutions, at low pH values with chloroform and carbon tetrachloride solutions of the reagent. Using the former solvent the rate of extraction of copper is shown to be slow, while mercury is rapidly extracted under the same conditions.4. The use of potassium cobalticyanide in combination with a chloroform solution of dithizone has enabled a method to be developed which eliminates interference of copper in mercury estimations; with the procedure given, mercury in concentrations of 1 to 55µg/l. may be determined in the presence of copper concentrations up to 69 mg./l.5. Copper may be determined in the same solution subsequent to the mercury estimation by the use of sodium diethyldithiocarbamate, after the solution has been made alkaline with ammonium hydroxide.