Spectrophotometric Determination of Copper and Bismuth Using 1-Methyl-(1-Methylol)-Ethyldithiocarbamic

The preparation of the reagent, amine salt of 1-methyl- (1-methylol)-ethyldicarbamic acid and its analytical applications for the determination of copper and bismuth were studied. The reagent was prepared from 2-amino-2-methyl-1-propanol with carbon disulfide. The amine is dissolved in absolute ethanol; carbon disulfide is added to this solution and the reaction allowed to go to completion under 36°C. The reaction mixture was poured into several large evaporation dishes and allowed to stand until yellow crystals formed. Purification of the crude product was carried out by repeated recrystaIIalization from water under 40°C. An analytical procedure was developed for the colorimetric determination of trace amounts of copper. The method was sensitive to concentration of copper of 0.1 ppm. at 430 mu. The study also covered the optimum concentration of the reagent used for quantitative determination of copper solutions. The interference effects of bismuth, cadmium, lead and zinc ions with the copper thiocarbamate molecule were measured. An analytical procedure was developed for the colorimetric determination of trace amounts of bismuth. The study also covered the optimum pH of the bismuth thiocarbamate system for quantitative determination. The method was sensitive to concentrations of bismuth of 1 ppm. at 380 mu