Excitation Temperatures and Electron Densities in a Magnetron Rotating Direct-Current Arc Plasma

Excitation temperatures and electron densities are reported for a magnetron rotating direct-current arc plasma with graphite furnace sample introduction. Temperatures obtained from emission line ratios of the Ar support gas are compared with values obtained for two analyte thermometric species, Zn(I) and Cu(I). At the anode surface, the plasma temperature is about 6500 K. The addition of an easily ionized element does not effect the Ar(I) temperature; however, a temperature increase of up to 1000 K was observed for the analyte thermometric species. At the anode surface, the electron density is about 1.0 × 10¹⁵ cm⁻³. The addition of an easily ionized element increases the electron density by about a factor of two. Possible explanations are given for the increases in temperature and electron density.