Ceramics-Silikáty 37, (3) 165 - 168 (1993)

Determination of small amounts of silicon in boron by direct AAS method with flame atomization in concentrations of Si 1-15 μg/ml in hydrochloric acid at the 1000-fold weight excess of boron (c = 1 mg/ml) was described. Decomposition of the sample (0.1 g) was performed by melting with addition of solid sodium hydroxide and sodium chlorate in a silver or a gold crucible and dissolving the melt after cooling down in hydrochloric acid. No effect of boron on the silicon signal was observed under given conditions. Maximum of silicon atoms absorption at a 251.6 nm line is at concentration of hydrochloric acid 0.2-0.35 mol/l. The results obtained by AAS method were compared with those achieved by a spectrophotometric determination of silicon as a blue silicomolybdate complex. Although the differences between the AAS results and the spectrophotomefric results are not statistically significant, the atomic absorption method is more suitable with respect to a significant saving of time needed for determination.