Sensitive determination of norfloxacin by the fluorescence probe of terbium (III)- sodium dodecylbenzene sulfonate and its luminescence mechanism.

The fluorescence system of the norfloxacin-Tb3+- sodium dodecylbenzene sulfonate (SDBS) was investigated in this paper. The experiments indicated that the fluorescence intensity of the Tb3+-SDBS was greatly enhanced by the norfloxacin. On the basis of the above findings, a sensitive fluorimetric method for determining the norfloxacin was established. The fluorescence intensity was measured by a 1-cm quartz cell with the excitation wavelength of 290 nm and the emission wavelength of 545 nm. The enhanced fluorescence intensity of the system (Delta F) showed a good linear relationship with the concentration of norfloxacin in the range of 5.0x10(-9) mol L(-1)-2.0x10(-6) mol L-1, its correlation coefficient was 0.9991 and the detection limit (S/N=3) was 1.2x10(-9) mol L-1. The presented method was used to determine the norfloxacin in real pharmaceutical samples. The luminescence mechanism was also discussed in detail. In the fluorescence system of the norfloxacin-Tb3+-SDBS, the SDBS not only acted as the surfactant, but also acted as the energy donor.