Fluorescence characteristic of enro floxacin sensitized by rare earth ion and its analytical application

The fluorescence characteristic of enrofloxacin-yttrium (III) (ENRX-Y3+) was investigated in the present paper. Experimental results indicated that Y3+ ion could greatly increase the fluorescence intensity of the system. From this, a simple and sensitive method of determining the ENRX was set up. The fluorescence intensity of the system was measured with a 1 cm quartz cell at the excitation wavelengths of 274 nm and the emission wavelengths of 424 nm. The optimal conditions were obtained as follows: pH = 5.5-6.2, 0.1 mol x L(-1) hexamethylenamine (HMA) buffer, the concentration of yttrium(III) was 1.0 x 10(-4) mol x L(-1). Under the optimal conditions, the fluorescence intensity of the system showed a good linear relationship with the concentration of ENRX in the range of 1.0 x 10(-9) - 5.0 x 10(-6) mol x L(-1), its correlation coefficient was 0.9981, and the detection limit (S/N=3) was 2.3 x 10(-10) mol x L(-1). Interferences of common metal ions and other pharmaceuticals usually used for the compatibility of medicines with the fluorescence intensity of the system were studied, and the results showed that most metal ions except Tb3+, Cu2+ and AP+ and the compatible medicines used together with ENRX did not interfere with its determination. The recovery tests in the compatible medicines were also performed, and the results showed that all the recoveries were in the range of 98.0%-107.0%, and RSDs were in the range of 0.9%-4.5%. The presented method was used to determine the ENRX in actual pharmaceutical samples which were used in the treatment for animals as compared with the reported method of terbium (III) luminescence probe, and the results were satisfactory. In addition, the luminescence mechanism of the ENRX-Y3+ system was also discussed.