Determination Of Fluoquinolones By Fluorimetry And Its Residues Analysis In The Water Environment

With the development of our society, a large amount of fluoquinolones(FQS) are used in the treatment and prevention of illness in human, veterinary and aquaculture, and as growth promoter in veterinary and aquaculture, hence sensitive and rapid pharmaceutical determination method is important for pharmacodynamics and pharmacokinetics. Besides, a great part of antibiotics and their active metabolite are excreted into the environment, the existence of antibiotics and their active metabolite in environment will probably influence the micro organization of the natural environment and lead to resistance in bacteria, and appearance of resistant bacterial and cross-resistance between human and veterinary. Hence research on the residue of antibiotics in environment and their environmental risk is of great importance in environmental treatment and ecological protection.In the first part, the fluorescence characteristic of enrofloxacin-yttrium (â…¢) (ENRX-Y³⁺) was investigated. Y³⁺ ion could greatly increase the fluorescence intensity of ENRX, and a sensitive method of determining ENRX was set up based on this. The fluorescence intensity of the system was measured in a 1 cm quartz cell at the excitation wavelengths of 274 nm and the emission wavelengths of 424 nm. Under the optimal conditions, the fluorescence intensity of the system had a good linear relationship with the concentration of ENRX in the range of 1.0×10^-9～5.0×10^-6 mol L^-1, and the detection limit (S/N=3) was 2.3×10^-10 mol L^-1. Interferences of common metal ions and some compatible pharmaceuticals on the fluorescence intensity of the system were also performed. The presented method was applied in the determination of ENRX in injection sample with satisfactory results. The luminescence mechanism was also discussed.In the second part, the synchronous fluorescence character of ENRX-Y³⁺ system was studied in detail and applied in the determination of ENRX in serum. The normal fluorescence system of Y³⁺-ENRX can be applied in the determination of pharmaceutical, but when it comes to the analysis of trace ENRX in serum, the spectra of intrinsic fluorescent content of serum would overlap with that of Y³⁺-ENRX system. However, the use of synchronous fluorescence can eliminate the disturbance completely. The synchronous fluorescence method have better sensitivity and selectivity than the normal fluorescence, besides, the pretreatment of serum is simple. The method was used to determine ENRX in chicken serum and human serum with satisfactory result.In the third part, a method was established to determine the concentration of four FQS in water samples. The method consisted of solid phase extraction, HPLC and fluorimetric determination, and is applied in the Qiantang River and Sibao sewage treatment plant (STP). Results indicted that the concentration of FQs in influent of Sibao STP was relatively higher than that of Sweden, while FQs in effluent was at similar concentration level as most countries. The removal rate of OFL and NOR in Sibao STP was 60～70%, slightly lower than the reported value of 70～80%, while that of CPX and ENRX was 29% and 49% respectively, obviously lower than the reported value. The relatively lower removal rate of FQs in Sibao STP may be caused by the different treatment process in different STPs. Besides, FQs is removed in STP mainly by adsorption to sludge, and the high temperature in Hangzhou in summer may have adverse effect on this process. Being affected by both the tide and the changeful weather in summer, the concentration of FQs in Qiantang River varied widely as well as that of Pearl River. When compared with Rearl river and Victoria Harbor in high water season, the concentration of OFL in Qiantang River was relatively higher, while NOR was lower. This minor difference in FQs concentration in these three areas might be caused by local pharmaceutical consumption, rainfall, runoff and efficiency of municipal sewage treatment.