Determination of cadmium in environmental materials by fast neutron activation analysis

Cadmium is determined by activation analysis with fast neutrons, obtained by irradiation of a thick beryllium target with 14.5-MeV deutrons. Cadmium-111m, formed via the ¹¹²Cd(n, 2n)^111mCd and ¹¹¹Cd(n, n′)^111mCd reactions, is separated by liquid—liquid extraction with zinc dithyldithiocarbamate in chloroform and measured with a Ge(Li) γ-spectrometer. For low concentrations, cadmium is precipitated as cadmium ammonium phosphate after the extraction. NBS and BCR reference materials were analyzed: for concentrations between 3 and 500 μg g^?1, the relative standard deviation ranges from 5 to 3% The results obtained for sewage sludge are compared with those obtained by reactor neutron activation analysis.