Study On New Methods Of Spectrophotometry,Fluorospectrophotometry And Resonance Rayleigh Scattering For The Determination Of Tetracaine Hydrochloride

Some simple,rapid and sensitive techniques of molecular spectrum analysis for the direct determination of tetracaine hydrochloride have been developed by investigating the interactions between tetracaine hydrochloride and fluorescein halide dyes using resonance Rayleigh scattering (RRS),frequency-doubling scattering(FDS),second-order scattering(SOS),fluorophotometry,and spectrophotometry in this paper.This work was a supplement of the methods for the determination of tetracaine hydrochloride and an expansion of the application scope of the RRS,FDS and SOS technology.The optimum conditions of the reaction and the properties of analytical chemistry were investigated and the reaction mechanism was discussed by AM1 quantum chemistry method.1.Absorption Spectra of the Reaction system for tetracaine hydrochloride with erythrosin and its analytical applicationIn a Britton-Robinson(BR)buffer solution of pH 4.0,erythrosine reacted with tetracaine hydrochloride to form 1:1 ion-association complex.As a result,the erythrosine's absorption spectra changed,the maximum absorption wavelength of the solution shifted from 526 nm to 558 nm,and there was an obvious fading peak at 516 nm.In the range of 0.1μg/mL to 7.2μg/mL,there was an excellent linearity between the concentration of TA·HCl andΔA of the solution at the maximum absorption and fading peaks.Based on it,a new spectrophotometry for the determination of TA·HC1 was proposed.The molar absorptivity was 3.30×10⁴ L·mol^-1·cm^-1for the fading method,2.22×10⁴ L·mol^-1·cm^-1for the revealing method and 5.52×10⁴ L·mol^-1·cm^-1for the dual-wavelength method.In this paper optimum reaction conditions and primary chemistry characteristics were discussed.The reaction mechanism was dicussed by quantum chemistry AM1 method.The method has been applied to determination of TA·HCl in human serum and urine samples with satisfactory results.The mean recoveries were from 98.1%to 103.3%.2.Fluorescence Quenching Reaction of Tetracaine Hydrochloride with Erythrosine and Their Analytical ApplicationsIn Britton-Robinson(BR)buffer solution at pH 4.0,erythrosine(ET)reacted with tetracaine hydrochloride(TA·HCl)to form an ion association complex that quenched the fluorescence of erythrosine and whose compound ratio was 1:1.The measurement wavelength of fluorescence quenching was located atλ_ex/λ_em=525 nm/556nm.The linear range for TA·HCl was from 0.28μg/mL to 4.8μg/mL,and its detection limit was 0.083μg/mL.The influence of coexisting substance was also inspected,and the result shows this method had a better selectivity.Therefore,a new fluorospectrophotometry,being high sensitive,sample and rapid,was developed to determinate TA·HCl at trace amounts.The method has been applied for the determination of TA·HCl in human serum and urine samples with satisfactory results.In this study,the spectra characteristics and the optimum reaction conditions were discussed quantum chemistry AM1 method.3.Resonance Rayleigh scattering spectra,second-order scattering spectra and frequency doubling scattering spectra of tetracaine hydrochloride-erythrosin system and its analytical applicationIn a Britton-Robinson(BR)buffer solution of pH 4.5,the interaction between erythrosine(ET) and tetracaine hydrochloride(TA·HCl)was studied by resonance Rayleigh scattering(RRS), frequency doubling scattering(FDS)and second-order scattering(SOS)combining with absorption spectrum.In a weak acidic medium,erythrosine reacted with tetracaine hydrochloride to form 1:1 ion-association complex.As a result,the new spectra of RRS,SOS and FDS appeared and their intensities were enhanced greatly.The maximun peak of RRS,SOS and FDS were at 342 nm,680 nm and 380 nm.The intensities of the three scattering were directly proportional to the concentration of TA·HCl in the range of 0.008～4.2μg/mL for RRS,0.027～4.2μg/mL for SOS and 0.041～4.2μg/mL for FDS.The methods had very high sensitivities and selectivities,and the detection limits were 0.003μg/mL for RRS,0.008μg/mL for SOS and 0.012μg/mL for FDS respectively.Therefore, a new method,being high sensitive,simple and rapid,was developed to determinate TA·HCl at trace amounts.The recovery for the determination of TA·HCl in blood serum and urine sample was between 97.0-103.8%.In this study,the enthalpy of formation and charge distribution were calculated by AM1 quantum chemistry method.The reaction mechanism was discussed.4.Absorption,fuorescence,Resonance Rayleigh scattering,second-order scattering and frequency doubling scattering spectra of tetracaine hydrochloride-Eosin Y system and its analytical applicationIn a weak acidic medium,Eosin Y reacted with tetracaine hydrochloride to form 1:1 ion-association complex,which not only resulted in the change of the absorption spectra at 513 nm and the quenching of synchronous fluorescence atλ_ex/λ_em=520 nm,but also resulted in the great enhancement of RRS,SOS and FDS atλ_ex/λ_em=279 nm,λ_ex/λ_em=240/480 nm andλ_ex/λ_em= 690/345nm.They were directly proportional to the concentration of TA·HCl and can be used to detect TA·HCl.Among them,the RRS method had the highest sensitivity and the detection limit was 0.005μg/mL.The recovery for the determination of TA·HCl in blood serum and urine samples was between 94.7-103.3%.5.Absorption,fluorescence,Resonance Rayleigh scattering,second-order scattering and frequency doubling scattering spectra of tetracaine hydrochloride-fluorescein dihalide dye system and its analytical applicationThe interaction of tetracaine hydrochloride(TA·HCl)with three fluorescein dihalide dyes such as dichlorofluorescein(Cl₂-F),dibromofluorescein(Br₂-F)and diiodofluorescein(I₂-F)was studied by absorption,fluorescence,resonance Rayleigh scattering(RRS),frequency doubling scattering(FDS) and second-order scattering(SOS)spectra.The results showed that the diiodofluorescein could react with tetracaine hydrochloride(TA·HCl)to form ion-association complexes,which not only resulted in the change of the absorption spectra and the quenching of fluorescence,but also resulted in the great enhancement of RRS,SOS and FDS.But the above interactions could not carry out after mixing tetracaine hydrochloride with dichlorofluorescein.In this work,the spectral characteristics of the absorption,fluorescence,RRS,SOS and FDS,the optimum conditions of the reaction and the properties of analytical chemistry were investigated.A sensitive,simple and new method for the determination of TA·HCl by using diiodofluorescein and dibromofluorescein as probes has been developed.TA-I₂-F system had a highest sensitivities than others,the detection limits for TA.HCl were 0.003μg/ml for RRS method,0.007μg/mL for SOS 0.049μg/mL for FDS,0.35μg/mL for spectrophotometry and 0.054μg/ml for fluorophotometry.There was a linear relationship between RRS,SOS,FDS,absorbance and fluorescence intensities and the drug concentration in the range of 0.01～0.6,0.024～1.2,0.16～1.2,1.2～3.6 and 0.18～4.8μg/mL,respectively.RRS method was more adapt to the determination of trace amounts of TA·HCl.In addition,the reaction mechanism and the reasons for the enhancement of scattering spectra and the energy transfer between absorption, fluorescence and RRS were discussed.