ANALYSIS OF SILICON DIOXIDE AND SILICON-NITRIDE POWDERS BY ELECTROTHERMAL VAPORIZATION INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY USING A TUNGSTEN COIL AND SLURRY SAMPLING

Slurry sampling in combination with ETV-ICP-AES was employed for the d irect determination of trace amounts of impurities in silicon dioxide and silicon nitride. The ETV device consisted of a double layer tungst en coil in a quartz apparatus. Spectral interferences and background e mission caused by tungsten ablation of the coil were reduced by coatin g the coil with tungsten carbide. The background was measured either w ith a high-purity sample, the suspension medium or close to the analyt e emission line, depending on matrix and analyte, or it was calculated using relative emission intensities of tungsten. The concentrations o f Al, B, Be, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb and Zn were measur ed simultaneously, whereas K and Na were determined in the sequential mode. Calibration was performed using the standard additions method. T he accuracy was checked by comparison with the results of independent methods. Limits of detection between 0.035 (Mg) and 130 mu g g(-1) (B) and between 0.01 (Be, Mg) and 34 mu g g(-1) (B) were achieved in sili con dioxide and silicon nitride, respectively.