| Resonance Rayleigh scattering(RRS) method is a new quantitative analytical technique which has progressively developed since 1990s.In recent years,RRS method has gained more and more attention and interest because of its simple operation and high sensitivity.At present,the RRS technique can not only be applied to the determination of biological macromolecules,inorganic ions, pharmaceuticals,and cationic surfactant,but also can be used to study and determination of critical micelle concentration and inclusion constant.At the same time,resonance non-linear scattering such as second-order scattering(SOS) and frequency doubling scattering(FDS) has been applied successfully as a new analytical technique.In this paper,some new methods for the determination of chitosan,sodium alginate,vitamin C and dopamine have been developed by means of RRS and resonance non-linear scattering.The main content and some conclusions of the thesis are as follows:1.Resonance Rayleigh scattering method for the determination of chitosan using Prussian Blue nanoparticles as a probePrussian Blue(PB) nanoparticles were prepared by mixing equimolar amount of FeCl3 and K4[Fe(CN)6]aqueous solutions in the presence of poly(vinylpyrrolidone)(PVP).Physical characteristics of the PB nanoparticles were studied by transmission electron microscopy(TEM), UV-vis and RRS.After mixing proper amount of chitosan with PB nanoparticles,the intensity of RRS increased.The RRS enhancement was induced from aggregation and assembly process of PB nanoparticles with chitosan.Under definite condition,the increase of RRS was proportional to the concentration of chitosan.A novel and simple method for the determination of trace chitosan using PB nanoparticles probe was developed.The detection limit(3σ)for chitosan was 7.46 ng/mL,and its linear range was 0.02-0.80μg/mL.In this work,the optimum conditions of this reaction and influencing factors have been investigated.2.Study on the interaction between sodium alginate and ethyl violet by absorption and resonance Rayleigh scattering spectra and their applicationIn weak acidic buffer medium,sodium alginate(SA) could react with ethyl violet(EV) to form an ion-association complex,which resulted in not only the change of the absorption spectra,but also the great enhancement of RRS.It was found that the relative intensities of RRS(ΔI) and absorbance (ΔA) were directly proportional to the concentrations of SA in a certain range.The results showed that the linear ranges were 0.36-2.25μg/mL for the spectrophotometric method and 0.009-0.30μg/mL for the RRS method.The detection limits(3σ) were 43.2 ng/mL for the spectrophotometric method and 2.8 ng/mL for the RRS method.Among them,the RRS method had the higher sensitivity.The characteristics of absorption,RRS spectra and the optimum conditions of this reaction and the influencing factors have been investigated.Based on the above researches, spectrophotometric and RRS methods for the determination of SA have been developed.The methods were applied to the determination of SA in tablet samples with satisfactory results.3.Resonance Rayleigh Scattering of K2Zn3[Fe(CN)6]2 nanoparticles and its application for the determination of vitamin CIn Britton-Robinson buffer medium(pH 4.43),potassium ferricyanide(K3[Fe(CN)6]) could react with vitamin C(VC) to produce potassium ferrocyanide(K4[Fe(CN)6]),which further reacted with Zn2+ to form potassium zinc hexacyanoferate K2Zn3[Fe(CN)6]2 nanoparticles.The shape and diameter of K2Zn3[Fe(CN)6]2 nanoparticles have been observed with transmission electron microscopy,which showed the shape of these nanoparticles was cubic and their average sizes were about 50 nm in the presence of 2.0×10-5 mol/L VC.The characteristics of RRS spectra of this reaction have been studied.The optimum reaction condition for the determination of VC has been investigated.It was found that the RRS intensity of the system at the RRS peak of 363.4 nm was proportional to the VC concentration in the range of 4.0-80.0μmol/L,and the detection limit(3σ) for VC was 0.075μmol/L.A novel and simple RRS method for the determination of VC based on the formation of K2Zn3[Fe(CN)6]2 nanoparticles has been established.4.Novel and sensitive methods for the determination of dopamine based on the resonance Rayleigh scattering,second-order scattering and frequency doubling scattering quenching effectsThree novel methods were designed for the determination of dopamine(DA) by means of the quenching effects on RRS and resonance non-linear scattering such as SOS and FDS intensities.In Britton-Robinson buffer medium(pH 6.02),I3- could react with DA to produce I-,which resulted in the decreases of the RRS,SOS and FDS intensities of the ethyl violet(EV)-I3- system,and the decreases of scattering intensity(ΔI) were directly proportional to the concentrations of DA in a certain range.The detection limit(3σ) for DA was 0.0195μmol/L for the RRS method,0.286 μmol/L for the SOS method and 0.0985μmol/L for the FDS method,respectively.In this work,the characteristics of absorption,RRS,SOS and FDS spectra of this reaction have been studied;the optimum reaction condition and influencing factors have been investigated.The methods were applied to the determination of DA in pharmaceutical samples with satisfactory results. |
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