EFFECT OF CATIONIC MICELLES ON THE FLUORESCENCE OF THE ZIRCONIUM-MORIN COMPLEX

The effect of cationic surfactants on the fluorescence of the zirconium-morin system is described. In sulphuric acid medium, the fluorescence intensity of this complex can be enhanced strongly by the cationic surfactant cetyltrimethylammonium bromide (CTAB). It was found that the decisive factor is the change in the composition of the analyte complex in the presence of CTAB. When the concentration of CTAB is near its critical micelle concentration, the absorptiometric measurement is favoured by the formation of a 1 :3 [Zr(IV): morin] complex. On increasing the CTAB concentration, a mixed-ligand complex with the composition of Zr(IV): morin: SO42- = 1: 1: 2 is formed, and the fluorescence intensity is enhanced dramatically. The role of CTAB in the formation of the mixed-ligand complex and the enhancement of the fluorescence is discussed.