Effect of oxygen gas as a matrix modifier on direct determination of cadmium and lead in blood and food samples by graphite furnace AAS

Abstract

An addition of oxygen gas to graphite furnace during the first ashing stage (20 s, 0.51 min^-1) of AAS determination of Cd and Pb greatly decreased the background absorption due to sample matrices such as milk, orange juice and blood. In case of Pb determination, the intensity of background absorption due to blood matrix decreased to one-tenth of that without oxygen gas treatment. The addition of oxygen gas also prevented the signal depression of Cd and Pb by the sample matrices.