THE DETERMINATION OF TRACE CADMIUM BY FLOW-INJECTION COLD VAPOR GENERATION AAS

A method for the determination of cadmium by FI-CVAAS (flow injection cold vapor generation atomic absorption spectrometry) using the reacti on with tetrahydroborate in acidic aqueous solutions was developed. Th e difference in sensitivities in aqueous, thiourea-, nickel- and thiou rea-nickel (cobalt)containing media using the Fl technique was studied . The chemical and hydrodynamic para meters for cadmium cold vapor gen eration were optimized and the interference of coexisting elements is discussed. The detection limit (3 sigma) was 30 ng/L with a sampling f requency of 240/h. The precision was 2.5% RSD (n=11) at the 4-mu g/L C d level. The method was applied to the analysis of water, urine, blood , human hair, geochemical soil and polluted soil standard reference sa mples. The results are in good agreement with the certified values of the standard materials. The recoveries in these sample solutions spike d with 4 mu g/L Cd are at 96-104%.