[en] Reactions between niobium or tantalum and salicylfluorone were studied in the presence of cationic, non-ionic and anionic surfactants. Tartrate, fluoride and sulfate initial solutions of niobium and tantalum were used. It was shown that niobium salicylfluoronate had a high molar absorptivity (>1.5x10⁵) in tartrate and sulfate solutions in the presence of cationic surfactants. The possibility was shown of determining 0.1-1.0 μg Nb in the presence of 5 μg Ta in sulfate solutions