Abstract: The effect of surfactants on the fluorescence of the zirconium-morin system was described In 0.12 mol/L H₂SO₄ solution,the fluorescent intensity of this complex can be enhanced by cationic surfactant,cetyltrimethylammonium bromide(CTAB),but no effect in HCl medium.It was found that the mechanism of the effects of CTABon the absorbance and fluorescence were different.The absorptiometric measurement was favored with the formation of 1:3(Zr(Ⅳ):morin) complex in the proper CTABconcentration(near the critical micelle concentration,cmc,of CTAB).With the CTABconcentration increasing,a mixed-ligand complex was formed,and the intensity of fluorescence was enhanced dramatically.The role of CTABin the formation of the mixed-ligand complex and the enhancement of fluorescence was discussd.Anew analytical method for the fluorometric determination of Zr(Ⅳ)was described also.The detection limits of the method is 0.2ng/mL,calculated with S/N=6.The linear range of the calibration graph was 0.2ng/mL～0.5μg/mL.The intensity of fluorescence is stable for at least 24 hours.From the study of interfering ions,it was deduced that the selectivity of the method is high,This is one of the.best system for determination of traces of zirconium.

Key words: Cationic micelles, Surfactants, Fluorimetry, Morin complex, Zirconium