Studies on Determinations of Metals by Extraction Method of Metal Organic Compound. III : Determinations of Lead, Silver and Mercury with Sodium Diethyl-dithiocarbamate

White precipitates or turbidities of lead, silver and mercury with sodium diethyl-dithio-carbamate were extracted with organic solvents, and their transmittancies were successfully measured at the wave length 340mμ of Beckman model DU spectrophotometer. By the measurements of the transmittancy of the extracts at the suited wave length, lead as small as 25γ, silver as small as 10γ and mercury as small as 50γ were determinable. Carbon tetrachloride was most useful for the extraction, and benzene, toluene, xylene and chloroform were also useful. The extractions were carried out completely at pH 3～9.5 in lead, pH 2.6～5, in silver and from 3N hydrochloric acid to pH 5.6 in mercury