The determination of silica by conway's microdiffusion technique

A new approach is suggested to the determination of silica. Silica is converted to volatile silicon-fluoride compounds by the action of hydrofluoric acid and is quatitatively isolated by Conway's microdiffusion technique in a polypropylene cell. To promote diffusion, a sulphuric acid medium is used; ethylene glycol serves as absorbent. Quantities of 20-70 μ SiO₂ per 0.5 ml were tested, with quantitative recovery. The silica was determined spectrophotometrically by the molybdenum blue method.