| Due to volume effect,surface effect,quantum size effect and macroscopic quantum tunneling effect,nanomaterials exhibit unique physical and chemical properties.Therefore,with broad prospects for application in many fields,they have become a hot and advanced research realm.Recently,more nanomaterials have been applied to analytical chemistry,in which nanoprobes and nano optical sensors developed by using their spectral characteristics have attracted much attention.Besides the application in ultraviolet-visible absorption spectra and fluorescence spectra analysis,other spectroscopic applications have also drawn considerable notice.Resonance Rayleigh Scattering(RRS) is a new analytical technique developed in 1990s.RRS is related to both the compelled vibration of the electrons in molecule and the electronic energy level transitions under the effect of the incident light electromagnetic field.Therefore it can offer more information about molecular structure and conformation,charge distribution,linkage nature as well as the reaction characteristics and so on.More attention has been paid to RRS method,since it is very sensitive and simple in monitoring some ions,some drugs and biomolecules.It has been also applied in the characterization and analysis of nanoparticles.In this thesis,the synthetic methods of cadmium selenide,cadmium selenide/ cadmium sulfide,cadmium telluride,cadmium telluride/ cadmium sulfide,cuprous selenide nanocrystals(NCs) and europium oxide nanorods were researched,and some nanocrystals with fine optical properties and reactivities were obtained by optimized synthetic methods.The size,structure and conformation of the nanocrystals prepared were characterized by various methods(transmission electron microscopy(TEM), high-resolution transmission electron microscopy(HRTEM),X-ray diffraction(XRD), infrared absorption spectrum(IR)).The properties of ultraviolet-visible absorption spectra,fluorescence spectra and RRS spectra of the NCs were investigated.The interactions of the NCs with some metal ions,drugs and biomolecules and the effect of the interactions on fluorescence and RRS spectra were examined.The possibility of the determination of metal ions,drugs and biomolecules by exploiting nanocrystals as fluorescence and RRS probes was explored.Therefore,it provides better conditions for further application of NCs probes in analytical chemistry.1.Study on syntheses,characterizations of cadmium selenide NCs and effects of their interactions with some metal ions and drugs on fluorescence and RRS spectraCadmium selenide NCs were obtained by the reaction of Cd(â…¡) with Se(â…¡),with aqueous or aqueous ammonia solution as solvent,KBH4 as reducer,selenium powder as selenium source,cadmium chloride as cadmium source and sodium mercaptoacetate (SMA),sodium mercaptosuccinate(SMS) and sodium citrate(SC) as wrapper.The structure and conformation of the NCs were characterized by TEM,HRTEM and XRD. The properties of ultraviolet-visible absorption spectra,fluorescence spectra and RRS spectra of the NCs were investigated.The effects of some metal ions and anticarcinogen doxorubicin hydrochloride(DH) on fluorescence and RRS of CdSe NCs were also studied.Among the wrappers,sodium mercaptoacetate(SMA) showed the best capping effect.CdSe NCs prepared under the conditions of Cd:Se:KBH4:SMA=1:0.5:2.0:2.5 and pH11.2 showed higher intensity of fluorescence and the clear edge of the NCs.The average diameter of the CdSe NCs was 2-4 nm.The maximum excitation and emission wavelengths were about 277 nm and 556 nm.The RRS peaks of CdSe NCs were located at about 320 nm and 559 nm.The interactions of CdSe NCs with certain metal ions in aqueous solution,such as Na(â… ),K(â… ),Mn(â…¡),Cu(â…¡),Cd(â…¡),Mg(â…¡),Ni(â…¡),Zn(â…¡),Co(â…¡),Cr(â…¢),and the effects of their interactions on fluorescence spectra and RRS spectra were investigated. The results indicate that Cr(â…¢)can enhance the fluorescence greatly,while Cu(â…¡) can result in the quenching of fluorescence of the NCs.The other ions have little influence on the fluorescence.This offers the possibility of determinations of Cr(â…¢) and Cu(â…¡) using CdSe NCs as fluorescence probe.The detection limit for Cr(â…¢) was 17 ng/ml, however the determination sensitivity of Cu(â…¡) was relatively lower.In alcohol solution,fluorescence peak of CdSe NCs shifted from 556 nm to 470nm.While the NCs reacted with Zn(â…¡),Ni(â…¡),Cr(â…¢),Cu(â…¡),and a new peak appeared at 407nm.The order of the fluorescence intensity was CdSe-Zn＞CdSe-Ni＞CdSe-Cr＞CdSe-Cu.The detection limit for Zn(â…¡) was 26μg/ml.Obviously, selectivities of interactions of metal ions with CdSe NCs in alcohol were poorer than those in aqueous solution.It was also found that the interactions of above ions with 8-Hydroxyquinoline(HQ) could cause fluorescence quenching at 407 nm.However,whether in aqueous or alcohol solution,the effects of metal ions on the RRS of CdSe NCs were unobvious.Therefore,the RRS methods mentioned above can not be applied in analysis.The effect of the interactions of doxorubicin hydrochloride(DH) with CdSe NCs on fluorescence and RRS was also studied.The results indicated that DH could result in the fluorescence quenching of the NCs,on the other hand,DH has little influence on the RRS spectra.That fluorescence quenching method exhibited high sensitivity and the detection limit for DH was 34 ng/ml.This provides a feasibility for utilizing CdSe NC as fluorescence probe to determine DH.2.Study on syntheses,characterizations of cadmium selenide/cadmium sulfide nanocrystals and effects of their interactions with some metal ions and drugs on fluorescence and RRS spectraCadmium selenide/cadmium sulfide NCs were prepared by the reaction of Cd(â…¡) with Se(â…¡) and S(â…¡),with water as solvent,KBH4 as reducer,selenium powder as selenium source,cadmium chloride as cadmium source,thioacetamide as sulphur source and sodium citrate(SC) as wrapper.The structure and conformation of the NCs were characterized by TEM,HRTEM and XRD.The properties of ultraviolet-visible absorption spectra,fluorescence spectra and RRS spectra of the NCs were investigated. The effects of some metal ions and aminoglycoside antibiotics on fluorescence and RRS of CdSe/CdS NCs were also studied. As the results indicated,CdSe/CdS NCs prepared under the conditions of Cd:Se: S:KBH4:SC=3.0:1.0:1.0:2.0:4.0 showed higher intensity of fluorescence and the average diameter of the NCs was 4.1-6.5 nm.The maximum excitation and emission wavelengths were about 232 nm and 620 nm.The fluorescence peak width at half height was only 39 nm.The effects of normal room light on the fluorescence characteristics of the CdSe /CdS NCs were investigated.It was found that the intensity of fluorescence of the NCs increased with the time extension.The exposed atmosphere of the NCs solution had great influence on fluorescence.The fluorescence was more enhanced under air than that under nitrogen.The effects of pH on the intensity of the fluorescence were also investigated.It was found that pH value had an obvious influence on the characteristics and intensity of the fluorescence.In pH 8.95-11.2,the fluorescence intensity was high and stable.The influences of the interactions of CdSe /CdS NCs with Cu(â…¡),Mn(â…¡), Hg(â…¡),Co(â…¡),Cr(â…¢) and Fe(â…¢) ions on fluorescence and RRS were investigated.It was found that the above six kinds of ions caused the fluorescence quenching.The conditions of interactions of the NCs with the ions were optimized.The correlation coefficients and linear ranges were obtained.The interactions had high sensitivities and the detection limits were 0.53 ng/ml(Cu(â…¡)),11.0 ng/ml(Mn(â…¡)),3.9 ng/ml (Hg(â…¡)),2.0 ng/ml(Co(â…¡)),2.9 ng/ml Cr(â…¢) and 11.6 ng/ml(Fe(â…¢)).This offers opportunities to determine above ions using CdSe/CdS NCs as fluorescence probe.The interactions of CdSe/CdS NCs with micronomicin sulfate(MS) and amikacin sulfate(AS) and its influence on fluorescence were investigated respectively.It was found that MS and AS could enhance the fluorescence of CdSe/CdS NCs in varying degrees.Under optimum conditions,the increased intensities had linear relationship with the concentrations of MS and AS.The detection limits for MS and AS were 18.7 ng mL-1 and 25.8 ng mL-1.This provides opportunities to determine aminoglycoside antibiotics using CdSe/CdS NCs as fluorescence probe.The resonance Rayleigh scattering(RRS) of CdSe/CdS NCs in aqueous solution was investigated.The scattering peaks were located at about 555 nm and 298 nm.It was found that Mn(â…¡),Hg(â…¡) and Co(â…¡) ions increased the intensity of RRS of the NCs and Cu(â…¡) ions decreased the intensity of RRS.There were linear relationships between the intensity of RRS and the concentration of the ions.But the detection limits for the ions of RRS method were lower than those of fluorescence quenching method. AS and MS did not cause the obvious change of RRS of CdSe/CdS NCs,so that the NCs could not be used to determine MS and AS by the RRS method.3.Study on syntheses,characterizations of cadmium telluride nanocrytals and effects of their interactions with some drugs on fluorescence and RRS spectraCadmium telluride nanocrystals(NCs) were achieved by reaction of CdCl2 with KHTe solution and were capped with sodium mercaptoacetate.The products were characterized by TEM,HRTEM,energy dispersive spectroscopy(EDS),XRD, fluorescence spectra and ultraviolet-visible spectra.The CdTe NCs were of cubic structure and the average size was about 5 nm.The fluorescence quantum yield of CdTe NCs aqueous solution increased from 37%to 97%after 20 days under room light.The maximum of fluorescence(λem) changed from 543 nm to 510 nm and the blue shift was 33 nm.The CdTe NCs aqueous solution can be kept stable for at least 10 months under 4℃in refrigerator.The resonance Rayleigh scattering(RRS) of CdTe NCs in aqueous solution was investigated.The maximum scattering peak is located at about 554 nm. The interactions of CdTe NCs with amikacin sulfate(AS) and micronomicin sulfate (MS) were investigated respectively.The effects of AS and MS on fluorescence and RRS of CdTe NCs were analysized.It was found that AS and MS could result in the fluorescence quenching of CdTe NCs and RRS enhancement of CdTe NCs.Under optimum conditions,the fluorescence quenching intensity and the enhanced RRS intensty had linear relationship with the concentration of AS and MS,respectively.The detection limits for AS and MS were 3.4 ng mL-1,2.6 ng mL-1 for fluorescence quenching method,15.2 ng mL-1,14.0 ng mL-1 for RRS method,respectively.The methods have high sensitivities so that CdTe NCs can be used as fluorescence probes and RRS probes for the determination of aminoglycoside antibiotics.4.Study on syntheses,characterizations of cadmium telluride/cadmium sulfide nanocrytals and their interactions with some ions and labeling of biomoleculesCadmium telluride/cadmium sulfide NCs were prepared by the reaction of Cd(â…¡) with Te(â…¡),with water as the solvent,KBH4 as reducer,tellurium powder as tellurium source,sodium mercaptoacetate as sulphur source and wrapper.The structure and conformation of the NCs were characterized by TEM,HRTEM and XRD.The properties of ultraviolet-visible absorption spectra,fluorescence spectra and RRS spectra of the NCs were investigated.The influences of the interactions of CdTe/CdS NCs with some ions on fluorescence and RRS were examined.CdTe/CdS NCs were used for specific labeling of bio-material.The CdTe/CdS NCs prepared under the conditions of Cd:Te:SMA=2:1:4.8 showed higher intensity of fluorescence.The average diameter of the NCs was about 6 nm.The fluorescence quantum yield was 98%.The maximum excitation and emission wavelengths were about 253 nm and 511 nm,respectively.The effect of pH value on fluorescence of the NCs was examined.It was found that in acidic medium,the fluorescence of the NCs was quenched and in pH 7.0-11.2,the fluorescence was the highest and stable.The influences of the interaction of CdTe /CdS NCs with some ions on fluorescence and RRS were investigated.It could be seen from the experiments that Cu(â…¡),Co(â…¡),Ni(â…¡) and Cr(â…¢) ions resulted in fluorescence quenching in varying degrees,among them,Cu(â…¡) exhibited the greatest quenching effect and the others were in the order of Co(â…¡)＞Ni(â…¡)＞Cr(â…¢).There were linear relationships between intensity of fluorescence and the concentration of the ions.The detection limits for the ions were 1.0 ng/ml(Cu(â…¡)),1.8 ng/ml(Co(â…¡)),3.5 ng/ml(Ni(â…¡)) and 3.4 ng/ml(Cr(â…¢)).Taken Cu(â…¡) as an example,the optimum reaction conditions and the influences of the coexisting substances were investigated.It was found that the fluorescence quenching method had certain selectivity,which offered a sound basis for the determination of the above ions,esp.Cu(â…¡) by utilizing fluorescence quenching method using CdTe/CdS NCs as fluorescence probe.When CdTe/CdS NCs reacted with Cu(â…¡),Co(â…¡) and Ni(â…¡),the intensity of RRS decreased.It was found that there are linear relationships between the intensity changes of RRS and the concentrations of ions in certain ranges.Compared with fluorescence methods,the sensitivities and the correlation coefficients of the RRS methods were lower.The CdTe/CdS NCs were used to label biomolecules.It was found that the CdTe/CdS NCs could combine with BSA,rabbit anti-goat IgG and goat anti-mouse IgG and made the proteins showed green fluorescence.The combination of CdTe/CdS NCs with goat anti-mouse IgG could keep the second antibody activity and their binding with mouse anti-human IgG could attain specific recognition.Using BSA to enclose the active points on the surface of the CdTe/CdS NCs binded by goat anti-mouse IgG,it could combine with CK19 mouse anti-human IgG on the surface of cells to realize the fluorescence labeling of the cells.5.Study on syntheses,characterizations and fluorescence spectra of Cu2Se nanocrystals and Eu2O3 nanorodsA simple new method under normal room temperature has been developed to prepare cuprous selenide NCs by the reaction of copper nitrate trihydrate with selenium and sodium mercaptoacetate in aqueous ammonia system.Cu2Se NCs were characterized by TEM,HRTEM,XRD,electron diffraction(ED),fluorescence spectrum and ultraviolet-visible absorption spectrum.Cu2Se NCs showed berzelianite structure with 20-40 nm in length and 10-20 nm in width.The fluorescence excitation and emission peaks were located at 253 nm and 585 nm,respectively.A simple process was proposed for synthesis of Eu2O3 nanorods.Eu2O(CO3)2·H2O nanorod monocrystalline and Eu2O3 nanorods were obtained by means of surfactant assistance,with aqueous butanol solution as the solvent and hexamethylene tetramine as the base.The samples obtained were analyzed and characterized by TEM,HRTEM, SEM and XRD.The Eu2O3 nanorod was about 80-300 nm in diameter and 1-5μm in length.The formation mechanism of 1D product was also discussed.The maximum absorption peak of the Eu2O3 nanorods was located at 317nm.A blue-shift of the peak was 47nm,which showed the obvious quantum-confinement effect.The peaks of fluorescence emission can be seen clearly at 329 nm and 617 nm.Cu2Se NCs and Eu2O3 nanorods mentioned above showed some fluorescence characteristics. However,they could not react with metal ions,medicines and biomolecules effectively because of their poor water-solubility.This should be improved by adopting new synthesis methods and surface modification in order to apply the NCs in analytical chemistry in the future effectively.
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