Fluorescence characteristics of complex system of rare earth terbium （Tb3＋）, norfloxacin, 1,10-phenanthroline（1,10-phen） and sur- factant sodium dodecyl benzene sulfonate （SDBS） had been studied by using fluorescence spectroscopy. In a buffer solution （pH=6.3）, the fluorescence intensity of the norfloxacin-Tb3＋ （NFLX-Tb3＋） system had been remarkably enhanced by SDBS and 1,10-Phen. When excited at 335 nm, a good linear relationship between fluorescence intensity of NFLX-Tb3＋ system and NFLX concentration was obtained in the range of 8× 10-8-4× 10-6 mol/L, and the linear equation was F=2× 10^8 CNFLX＋22.7 with correlation coefficient of 0.9959. In addition, this method was compared with some previous literatures, the proposed method had relatively higher sensitivity and lower detect limit. The method was sim- ple, rapid, sensitive, practical and suitable for direct analysis of pharmaceutical preparation. It was successfully applied to determine the cap- sules, human serum and urine in real pharmaceutical samples.
