Oscillopolarographic determination of microsillicon in seawater

A new oscillopolarographic method for the determination of Si (Ⅳ) is described in this paper. In the system HCl-Sb(Ⅲ)-Mo(Ⅵ)-NaCl-ethyl alcohol, Si (Ⅳ) with Sb (Ⅲ) and Mo (Ⅵ) form ternary heteropoly acid. The anion of ternary heteropoly is adsorbed on the dropping mercury electrobe and under proper electric potentials reduced quickly into heteropoly blue. The process of electrochemical reaction will produce a sensitive polarographic wave with peak potential at -0.30(Vs. SCE). The lower limit of determination is 8×10^-8 mol/dm³. This method is sensitive, accurate and extremely rapid for the determination of micro-silicon in seawater.