Investigation of possibility of using azo dyes of chromotropic and H-acid derivatives for vanadium small amount determination

Studied is the interaction of vanadium (4) and azo dyes, which are chromotropic and H acid derivatives, to choose the most sensitive and selective reagent for vanadium small amount determination by the spectrophotometric method. It is shown that the best reagents are the acid chrome blue K and sulphonazo, where hydroxy-groups, able to form complexes, are present. Sulphanazo is less preferable, because the optical density dependence on medium pH is observed. Reaction sensitivity of vanadium with sulphonazo is equal to 4x10-3 μg/ml at l=50 mm. Selectivity factor for attendant ions is: for Zn - 100000, Mn - 100000, Cr - 150, Al - 10 (in the presence of natrium fluobarate it is 2000)