Effect of organic gases on molecular formation reactions in the DCP

The primary problem with sample introduction in the DC plasma is not the creation of the analyte aerosol, but the introduction of the analyte aerosol into the atom cell. Unlike those atom cells in which the sample is constrained to pass through the center of the flame or plasma, in the DCP the sample is introduced under the plasma and cannot easily be forced to penetrate the plasma core. Hence, an aqueous aerosol is deflected around the plasma and resides on the outside skin of the plasma, which has a much lower excitation temperature. This deflection is thought to hinder the vaporization and molecular dissociation processes of the analyte. Also, it is now believed that significant metal oxide formation may occur in this region due to entrainment with air, leading to a reduced metal atom concentration. 7 refs., 8 figs.