ISO 9683-1:2006 specifies a spectrophotometric method using N-benzoyl-phenylhydroxylamine (BPHA) for the determination of the mass fraction of vanadium in iron ores.

This method is applicable to mass fractions of vanadium between 0,005 and 0,5 % in natural iron ores, iron ore concentrates and agglomerates, including sinter products.