Suppression of Contamination for Trace Analysis of Silicon by Molybdosilicate Blue Spectrophotometry after Silicon Tetrafluoride Separation

For the determination of trace-level elements in metallic samples, several chemical procedures for the separation and pre-concentration from the matrix metals have been employed. However, troublesome problems are frequently encountered in the chemical separation procedure. Especially, the analytical values may contain errors due to contamination of the analyte from several experimental situations; this phenomenon results in an increase and the variance in a blank value in analysis. For decreasing the blank value, it is necessary to evaluate the cause for contamination through the analytical procedure. The authors investigated the effects of contaminants attributed to the experimental tools, reagents and an environment on the blank value for the trace analysis of silicon in metallic samples in molybdosilicate blue spectrophotometry after silicon tetrafluoride separation. For analyzing trace silicon with better precision, the experimental instruments have to be cleaned and reagents containing the lowest concentration of silicon have to be selected and employed. Moreover, the analytical operations should be carried out in a short time and amounts of the reagents should be reduced as much as possible.