Highly sensitive determination of carbon-and hydrogen-containing impurities in silicon tetrachloride by gas chromatography

Procedures were developed for the direct gas-chromatographic determination of impurities of organochlorine substances, chlorosilane. and alkylchlorosi lane in silicon tetrachloride and for the.-as-chromatographic analysis with matrix subtraction by preliminary hydrolysis of silicon tetrachloride and subsequent extraction of organochlorine impurities with an organic solvent. It was found that the major impurities in high-purity silicon tetrachlorid e obtained by the rectification of the by-product in the production of tric hlorosilane are trichlorosilane, methyltrichlorosilane, methyldichlorosilan e, chloroform, and carbon tetrachloride. Detection limits of impurities are 10(-5)-10(-7) Wt %, which is lower than those reported in the literature b y 1-2 orders of magnitude.