Slurry sampling of silicon nitride powder combined with fluorination assisted electrothermal vaporization for direct determination of titanium, yttrium and aluminum by ICP-AES

The vaporization behavior of silicon and three refractory trace elements (A l, Ti and Y) were studied in the presence and absence of a PTFE emulsion as fluorinating reagent and applying an electrothermal ICP-AES coupled system . It was found that during a 60 s ashing step at 700 degrees C about 90% of 100 mu g of Si3N4 can be decomposed and evaporated without considerable lo sses of the trace elements investigated. Calibration could be carried out b y the standard addition method and the calibration curve method applying sp iked slurries and aqueous standard solutions with peak height intensity mea surements, respectively. The detection limits varied from 0.11 mu g g(-1) ( Al) to 0.09 mu g g(-1) (Ti) with RSD 1.9-4.2%.