Quantitative analysis of alkali silicate solutions by ICP AES

SiO2 and Na2O concentrations of alkali silicate solutions can be determined by ICP AES using scandium as an internal standard. Diluting the samples with water causes problems with the sample nebulization. It is possible to avoid this by adding KOH, but a higher pH value leads to precipitation of scandium. Better results are obtained by treating the samples with HF to cause the reaction of SiO2 to H2SiF6. For calibration a standard glass of the DGG is used.