Rapid determinatioii of microgram amounts of silicon in metals by fluoride separation-molybdenum blue speGtropbotometry

Abstract

Volatility of silicon tetrafluoride compounds was utilized to separation of microgram amounts of silicon in high purity metals. In order to generate silicon tetrafluoride completely without heating, the presence of sulfuric acid about twice amounts of the sample solution was required before addition of hydrofluoric acid. The liberated silicon tetrafluoride was absorbed into a solution containing boric acid by oxygen carrier gas, then silicon in the absorbent was determined by molybdenum blue spectrophotometric method. By this method, microgram amounts of silicon (1 ppm) could be rapidly determined within (40~45) min, and the coefficient of variation in determination of 0.0006 % silicon in pure iron was about 6.4 %. Furthermore, the procedure is applicable to silicon in Ga-As semiconductor, and in other metals. © 1984, The Japan Society for Analytical Chemistry. All rights reserved.