The absorptiometric determination of silicon in water. Part III. Method for determining the total silicon content

Abstract

A method is described for determining the total silicon content of water a t low concentrations. I t consists in evaporation and subsequent fusion of samples with sodium carbonate ; the resulting sodium silicate is determined absorptiometrically as reduced or-molybdosilicic acid. The absorptiometric procedure is precise, and the major errors, a t low concentrations, arise in the fusion procedure. The standard deviation, for samples between 2 and 20 ml, was about 0.3 p g of silica over the range 0 to 60 pg of silica. Four samples can be analysed in duplicate per day.t "Reactive" silicon-mainly monomeric and dimeric silicic acid-is defined in this paper as those forms of silicon that react with ammonium molybdate in 10 minutes to form molybdosilicic acid under the conditions of the method given in Part I1 of this series.' * The entire procedure was carried out.