| Abstract: | Large emission intensity fluctuations are observed from analyte species in inductively coupled plasmas. Relative standard deviations are as large as 71% when emission is viewed with time resolution of 10 microseconds. Low in the plasma, peaks in atom emission intensity are accompanied by depressions in ion emission. This behavior appears to be due to local cooling by aerosol droplets. High in the plasma, peaks in atom emission are followed by peaks in ion emission. These emission spikes result from atomization and ionization of analyte from vaporizing particles. Laser light scattering experiments show that droplets or particles exist in a conventional 1.0-kW plasma up to 20 mm above the load coil. Emission signals detected high in the plasma correlate with laser light scattering signals below. |
