The absorptiometric determination of silicon in water. Part VI. Determination of polymeric silicic acid

Abstract

A method is described for determining polymeric silicic acid in water. The sample is first digested with sodium hydroxide to convert the polymer into “reactive” silicon, which is then determined absorptiometrically. The extent to which certain other forms of “non-reactive” silicon are determined has also been established. In conjunction with methods for “reactive” and total silicon, the method is useful in helping to distinguish between the different forms of “non-reactive” silicon that may occur in samples. At concentrations of about 0·02 p.p.m. of silica, the standard deviation of analytical results was about 0·001 p.p.m. of silica. Ten samples can be analysed in about 3 hours.