Simultaneous determination of phosphorus. arsenic and germanium and the separation of silicon and arsenic by solvent extraction

A simple, rapid, accurate and reliable method for the simultaneous determination of phosphorus, arsenic and germanium as their heteropoly blue complexes is reported. The method involves selective extraction of phosphomolybdic acid at pH 1.0-0.8, and selective extraction of germanomolybdic acid by isooctyl alcohol at pH 0.4, followed by back-extraction of the germanomolybdic acid with water, and reduction of arsenomolybdic acid in the remaining aqueous phase. A rapid and reliable method is also reported for the simultaneous determination of arsenic and silicon by selective extraction of silicomolybdic acid with isooctyl alcohol at pH < 0.4 and the back-extraction of the silicomolybdic acid with water; arsenic is determined in the remaining aqueous phase. The procedure can be applied to the simultaneous determination of phosphorus, arsenic and silicon.