Photometric determination of traces of molybdenum after sulfide precipitation

A photometric method for traces of molybdenum in silicate rocks and similar materials is described, in which molybdenum is isolated as the sulfide from the 1acidified leach of the sodium carbonate melt. Antimony(V) sulfide is used as collector. Molybdenum is thus separated from phosphorus, vanadium, tungsten, uranium, and some other elements. The final determination is made by the familiar thiocyanate-stannous chloride method with isopropyl ether as extractant. The method is particularly suitable for the determination of molybdenum, in the presence of relatively much tungsten.