Abstract
Flow injection analysis has been developed for the spectrophotometric determination of silicon in silicate rocks at 415nm. A powdered sample was decomposed with small amounts of hydrochloric and hydrofluoric acids in a Tuf-tainer vial by microwave heating. The contents in the vial were diluted with water after the addition of boric acid. The sample solution thus obtained contains silicon in concentrations of 200-380μg g-1 as silicon dioxide. It was injected to the FIA system without any dilution. Analytical results for silicon in 22 standard rocks from United States Geological Survey, Geological Survey of Japan and Canadian Certified Reference Materials Project agreed well with the proposed values. This method permitted 30 determinations per hour.
