Addition of small amounts of helium and hydrogen to the working gases in slurry nebulization inductively coupled plasma atomic emission spectrometry for the analysis of ceramic powders

Small amounts of hydrogen and helium were added to the internal gas flow of a 1.5 kW inductively coupled argon plasma to investigate the capabilities of the resulting mixed gas plasmas with respect to the particle evaporation in slurry nebulization inductively coupled plasma atomic emission spectrometry for the analysis of refractory ceramic powders. The addition of up to 15% v/v of hydrogen to the internal gas results in an increase in the Al and Si line intensities for slurries of Al2O3 and SiC powders of up to 20-100%, after optimization of all parameters. The corresponding increases in the recoveries were found to be of the order of 9-14% for Al2O3 and SiC powders with sizes of 0.3-18 and 0.3-12 mu m, i.e., from 48 to 62% and from 43 to 52%, respectively. Additions of helium, however, were only 50% as efficient. These effects refer to a more efficient evaporation of the powders in the plasma. Axially resolved measurements of analyte line intensities for both slurries and solutions also reflect the influence of the amounts of added hydrogen helium on the plasma geometry.