Study Of The Fluorescence Analysis Of Quinolones And The Interactions Between Flavones And Proteins

Fluorescence analysis has the advantages of high sensitivity and selectivity. This paper adopts the fluorescence spectroscopy method to establish new methods for the fluorescence analysis of quinolone drugs and to study the interaction between flavonoids and human serum albumin. This paper involves the following research work:(1) with rare earth ion terbium as fluorescent probe, this paper established a simple, sensitive new method for the fluorescence analysis of trace norfloxacin. The determination conditions were optimized. As a result, when pH was at 6.0 in the hexamine - hydrochloric acid buffer solution, energy transfered best. The detection limit of this method was ten times lower than that with direct fluorescence method. The method was used to determine the drug content in the capsule and the recovery rate was 90.6%. The reaction mechanism was discussed.(2) Using rare earth ion terbium as fluorescent probes, the reaction conditions of levofloxacin-Tb3+system were optimized. In this work ,a new method for the determination of levofloxacin was established. The linear range is 1.0×10-8-5.0×10-6 mol·L-1 and the detection limit is 4.5×10-9 mol·L-1. The reaction mechanism was discussed. Levofloxacin -Tb3+ complexes can make the LM-type fluorescence characteristics of rare earth ions Tb3+ sensitive, turn levofloxacin broadband and short-wavelength fluorescence peak into sharp line, long-wavelength Tb3+ fluorescence peak, thus to make it possible to avoid interference of proteins and other substances in order to determine the drugs from biological samples.(3) This part studies the interaction between luteolin and human serum albumin (HSA) using fluorescence quenching spectra, synchronous fluorescence spectra and ultra-violet spectra. The results show that luteolin has a strong ability to quench the fluorescence of HAS. The Stern-Volmer curve of the fluorescence quenching of HSA by luteolin indicates that the quenching mechanism between luteolin and HSA is a static quenching. According to the F?rster theory of non-radiation energy transfer, the binding distances (r) and the binding constants (KA) are calculated. The thermodynamic parameters show that the interaction between luteolin and HSA is driven mainly by hydropH obic force. Synchronous spectra are used to investigate the conformational changes of HSA. (4)This part investigates the interaction of Genistein with human serum albumin (HSA ) by fluorescence quenching spectra, synchronous fluorescence spectra and ultra-violet absorption spectra. The results show that the quenching mechanism of the intrinsic fluorescence of HSA by Genistein is due to forming the Genistein-HSA complex, which results in static quenching procedure. The binding constants (KA) are 1.00×106 (27℃),1.66×106 (37℃) and 5.25×106 (47℃) , respectively. According to the F?rster theory of non-radiation energy transfer, the binding distances (r) are 2.59 nm (27℃),2.65 nm (37℃) and 2.90 nm (47℃) , respectively. The thermodynamic parameters show that the binding power between Genistein and HSA is mainly the electrostatic interaction. Synchronous spectrum are used to investigate the conformational change of HSA.