The New Determination Method For Fluoroquinolones Antibiotics By Resonance Rayleigh Scattering Technique

Resonance Rayleigh scattering(RRS)technique is a new analytical technique developed in 1990s.It has attracted more and more attention because of its high sensitivity,simplicity and good selectivity.It has been extensively and successfully unitized to study and determination of biological macromolecules,trace metal ions, nonmetal ions and nanoparticle probe et al.In the last years,there are more and more studies and applications by RRS technique in pharmaceutical field,it indicated RRS technique has a good applied future.But it is rarely applied in fluoroquinolones antibiotics field.Therefore,taking fluoroquinolones antibiotics which are applied widely in clinic as studied objects,we investigated the interaction between fluoroquinolones antibiotics with some dyes,metal ions,and the interaction between metal-fluoroquinolones chelates with some small molecules(dyes)by RRS method.The spectral characteristics,the affecting factors and the properties of analytical chemistry and their analytical applications have been studied,and a series of methods to determinate fluoroquinolones antibiotics were developed.Besides,the reaction mechanism and the reasons for enhancement of RRS were discussed by the absorption spectra,the fluorescence spectra and the quantum chemistry method.1,Three methods to the determination for fluoroquinolones by the erythrosine as probeIn pH 4.4-4.5 Britton-Robinson(BR)buffer solution,fluoroquinolone antibiotics (FLQs)including ciprofloxacin(CIP),norfloxacin(NOR),levofloxacin(LEV)and lomefloxacin(LOM)could react with erythrosine(Ery)to form 1:1 ion-association complexes,which not only resulted in the changes of the absorption spectra and the quenching of fluorescence,but also resulted in the great enhancement of resonance Rayleigh scattering(RRS).These offered some indications of the determination of fluoroquinolone antibiotics by spectrophotometric,fluorescence and resonance Rayleigh scattering methods.The detection limits for fluoroquinolone antibiotics were in the range of 0.097～0.265μg·mL^-1for absorption methods,0.022～0.100μg·mL^-1for fluorophotometry and 0.014～0.027μg·mL^-1for RRS method,respectively.Among them, the RRS method had the highest sensitivity.In this work,the spectral characteristics of the absorption,fluorescence and RRS,the optimum conditions of the reactions and the properties of the analytical chemistry were investigated.The methods have been successfully applied to determination of some fluoroquinolone antibiotics in human urine samples and tablets.Taking CIP-Ery system as an example,the charge distribution,the enthalpy of formation and the mean polarizability were calculated by density function theory(DFT)method.In addition,the reasons for the enhancement of scattering spectra were discussed by the absorption spectra,the fluorescence spectra and the quantum chemistry method.2,Two methods to the determination for erythrosine by the as fluoroquinolones probe2.1,RRS method to the determination for erythrosioneThe reaction between erythrosine and fluoroquinolone antibiotics(FLQs)including ciprofloxacin(CIP),norfloxacin(NOR),ofloxacin(OF),levofloxacin(LEV), sparfloxacin(SPA)and lomefloxacin(LOM)was studied by resonance Rayleigh scattering methods.Our experiment conclusion indicated the reaction between erythrosine and fluoroquinolones resulted in the great enhancement of RRS,the scattering intensities are enhanced with the increase of erythrosine concentration,so it can be used to determinate erythrosine.Among of six systems,sparfloxacin-erythrosine system has the highest sensitivity which the detection limits is 7.14 ng·mL^-1.The optimum conditions of reaction excluding pH,concentration and ionic intensity,and the effects of foreign substances have been investigated.Based on the reaction between flouroquinolones and erythrosine,we developed a new method of determination for erythrosine by RRS.The method is simple,rapid and sensitive,can be applied to determinate erythrosine in some candies and drink.In addition,the reasons for the enhancement of scattering spectra were discussed by the absorption spectra,the fluorescence spectra and the density function theory(DFT)method.2.1,The determination for erythrosione by the quenching of fluorescence methodThe influence on fluorescence spectra of the reaction between erythrosine and fluoroquinolone antibiotics(FLQs)including ciprofloxacin(CIP),norfloxacin(NOR), ofloxacin(OF),levofloxacin(LEV),sparfloxacin(SPA)and lomefloxacin(LOM)was studied.The result indicated the reaction between erythrosine and fluoroquinolones resulted in the quenching of fluorescence.By using flouroquinolones as probes,we develope some quenching of fluorescence methods to determinate erythrosine.There are some differences in their sensitivities of six systems,which the detection limits are from 0.016 to 0.027μg·mL^-1.Taking LEV-Ery system as an example,the optimum conditions of reaction excluding pH,concentration and ionic intensity,and the effects of foreign substances have been investigated.In addition,the reasons for the quenching of fluorescence were discussed. 3,The system of fluoroquinolone and cerium(â…£)In pH 4.0-5.0 HCl-NaAc buffer solution,cerium(â…£)can react with fluoroquinolones on oxygen of carbonyl to form very stable chelate complexes which are bidentate ligands.The reactions not only result in the changes of absorption spectra, a new peak appear at 205 nm,and make the characteristic peak of fluoroquinolones to bathochromic shift,but also results in the enhancement of RRS,the studied five medications systems have similar spectra which the maximum scattering peaks locate on 381 nm,and there are the small peaks at 534 nm.The scattering intensities are enhanced with the increase of medication concentration,so we develop a new method to determinate fluoroquinolones.In this paper,the optimum conditions and properties of the analytical chemistry are investigated.The methods are good selective,simple,rapid stable and have high sensitivity,so they can be applied to determinate fluoroquinoloncs on pharmaceutical and fish meat,and the results are satisfactory.4,The system of Cu(â…¡)-fluoroquinolone chelates with erythrosineIn pH 4.2-5.0 Britton-Robinson buffer solution medium,fluoroquinolone antibiotics(FLQs),such as ciprofloxacin(CIP),norfloxacin(NOR),ofloxacin(OF), levofloxacin(LEV),lomefloxacin(LOM),and sparfloxacin(SPA),react with Cu(â…¡)to form chelate cations,which further bind with erythrosine to form the ion association complexes.They can result in the changes of the absorption spectra.Simultaneously, erythrosine fades obviously and the maximum fading wavelength is located at 526 nm. The fading reactions have high sensitivities.Thus,new spectrophotometries of determination for these drugs are developed.The ion -association reactions result in the quenching of fluorescence,which also have high sensitivities.The detection limits for six antibiotics are in the range of 7.1～12.2 ng·mL^-1Furthermore,the reactions can result in the enhancement of resonance Rayleigh scattering(RRS).The maximum scattering peaks of six ion-association complexes are located at 566 nm,and there are two small RRS peaks at 333 nm and 287 nm.The detection limits for fluoroquinolone antibiotics are in the range of 1.70～3.10 ng·mL^-1for RRS method.Among the above three methods, the RRS method has the highest sensitivity.In this work,we investigated the spectral characteristics of the absorption,fuorescence and RRS,the optimum conditions of the reactions,and the properties of the analytical chemistry.In addition,the mechanism of reactions was discussed by density function theory(DFT)and AM1 methods.5,The system of Fluoroquinolone Antibiotics-Cobalt(â…¡)-Congo RedIn pH 4.5-6.5 Britton-Robinson buffer medium,fluoroquinolone antibiotics(FLQs) such as ciprofloxacin(CIP),norfloxacin(NOR),ofloxacin(OF),levofloxacin(LEV) react with Co²⁺to form chelate cations,which further bind with Congo Red to form the ion association complexes.It results in the great enhancement of resonance Rayleigh scattering(RRS).Four FLQs reaction products have similar spectral characteristics and their maximum RRS wavelengths are all located at 560 nm,and there are two smaller RRS peaks in 382 nm and 278 nm.The linear ranges and the detection limits of four FLQs are 0.026-2.64μg·mL^-1and 7.68 ng mL^-1for CIP,0.045-3.20μg·mL^-1and 13.00 ng mL^-1for NOR,0.037-4.00μg·mL^-1and 11.24 ng mL^-1for OF,0.039-4.00μg·mL^-1 and 11.80 ng·mL^-1for LEV,respectively.A simple,rapid and sensitive RRS method for the determination of FLQs in pharmaceutical formulation and human urine sample was developed.The reaction mechanism has been also investigated.