Direct analysis of silicon carbide by fluorination assisted electrothermalvaporization inductively coupled plasma atomic emission spectrometry usinga slurry sampling technique

Slurry sampling in combination with fluorination assisted electrothermal va porization inductively coupled plasma atomic emission spectrometry (ETV-ICP -AES) was employed for the direct determination of trace impurities in sili con carbide ceramic powders. The vaporization behaviors of silicon and five trace elements (Al, Cr, Cu, Fe and V) were studied in the presence and abs ence of polytetrafluoroethylene (PTFE) as fluorinating reagent. It was foun d that, during a 60 s ashing step at 800 degreesC, about 97% of 100 mug of SiC can be decomposed and evaporated without considerable losses of the tra ce elements investigated. Calibration was performed using the standard addi tion method and the calibration curve method, applying spiked slurries and aqueous standard solutions, respectively. The accuracy was checked by compa rison of the results with those obtained by solution fluorination assisted ETV-ICP-AES and pneumatic nebulization (PN)-ICP-AES involving wet chemical decomposition of the sample. Detection limits between 0.3 mug g(-1) (Al) an d 0.08 mug g(-1) (Cu) were achieved. The precision, expressed as the relati ve standard deviation (RSD), was between 6.0% (for 18.2 mug g(-1) of Cr) an d 2.8% (for 177 mug g(-1) of Fe).