Polarographic and potentiometric determination of the stability constants of lead, cadmium and zinc complexes with dithiocarbaminoacetic acid

The stability constants of lead, cadmium and zinc dithio-carbaminoacetic acid (TCA) complexes have been determined. Lead and cadmium TCA complexes were studied by means of a polarographic method. A competitive polarographic method was used for the study of zinc TCA complexes. Zinc and cadmium TCA complexes were also studied potentiometrically with an amalgam electrode. The stability constants found were: lead, log beta(2) = 13.2; cadmium, log beta(1) = 5.4 (pot.), log beta(2) = 9.3 (pot.), log beta(3) = 13.7 (pot.), 13.6 (pol.); zinc, logbeta(1) = 3.4(pot.), <3.8(pol.), logbeta(2) = 6.6 (pot.), 6.4(pol.), logbeta(3) = 8.9 (pot.), 9.3 (pol.).