On the Dithizon Method for the Determination of Mercury

For the Determination of mercury, benzene was a convenient solvent for the simplification of procedures. The reproducibility of mercuric ion determined was higher than the other procedures because of the removal of excess reagent and interfering metals of each 1.0 mg of Cu2+, Bi3+ and Sn2+ ions by washing of benzene layer with ammoniac solution of EDTA. The interference of up to 30 μg of Ag+ ion was also prevented by washing with sodium chloride solution. The digestion time of samples was shortened by the use of sulfuric acid, hydrogen peroxide and potassium permanganate, and the extraction with n-hexane could remove the residual fat attributable to low recovery of mercuric ion in the digestion.