Spectrophotometric determination of silicate in rain and aerosols by flow analysis Original Research Article

A flow analysis (FA) procedure for the measurement of soluble silicon with respect to the total Si concentration is described. After solubilization in H2O, in alkaline solutions or in concentrated HF, silicon is determined by the molybdenum blue spectrophotometric method. The effects of Si complexation by F− are considered as are the decomplexing capacities of H3BO3 or Al3+. The proposed method is applied to samples of rain and of aerosols on filters, collected in Florence. For both kind of samples, the water soluble silicon content is about 1% and practically independent of the total silicon content.