Methods were developed for the separation of tungsten from molybdenum by liquid-liquid extraction and extraction chromatography
using thiocyanate and a quaternary ammonium salt, Zephiramine. Tungsten was extracted into chloroform as an ion associate
of tungsten(V)-thiocyanate complex and Zephiramine cation was retained on a column of Teflon powder coated with Zephiramine,
but molybdenum(III) was neither extracted nor retained. The extraction chromatographic method was successfully applied to
the determination of trace amounts of tungsten in molybdenum by neutron activation analysis.