Pulse Polarographic Determination of Nanogram Amounts of Silicon

Abstract

A procedure has been developed for the pulse polarographic determination of nanogram amounts of silicon based on the reduction of β-12-molybdosilicate. The heteropolyacid is formed in the presence of methyl ethyl ketone and excess of molybdate is masked .5 with citrate. A low concentration of molybdate (approx. 5×10⁻⁵ M) is used in order to ensure that low blanks are obtained, and, at these low levels of molybdate and silicate, formation of β-12-molybdosilicate is complete after eighteen hours. A one-hundredfold ratio of phosphate or arsenate does not interfere.