The Study Of Vitamin By FT-Raman Spectroscopy And Surface Enhanced Raman Scattering (SERS)

Raman spectrum belongs to molecular spectrum;it is an important tool for researching the structure of molecule.The Raman spectroscopy can provide the plenty of information about the inherent frequency and the inner interaction of molecular vibration,behavior and the reaction of the interface.With the expansion of frequency range of modem laser and the enrichment of light detection method,sensitivity of Raman spectrum has made great progress.Combined with other analytic methods such as IR,AES,XPS,SEM,TEM,AFM,MS,etc.,Raman spectrum is sure to have a broader field of application.As it is known,the phenomenon that the Raman vibration of sample molecules absorbed on the rough surface of silver sol is obviously enhanced is named as Surface Enhanced Raman Scattering (SERS),Now SERS is widely used as a highly powerful analytical tool to investigate molecular structure and interaction between molecules and metal surfaces resulting in strongly increased Raman signals from molecules which have been attached to nanometer sized metallic structures.Vitamin is a kind of nutriment which is necessary for human body to maintain normal physiological function.Because of its indispensability to human body,vitamin has been an interesting research object in medical science,electrochemistry and inorganic chemistry.If the structural and related information of vitamin is clear,we can do thorough research in vitamin absorption process in human body.So the purpose of our research is to analyze and detect the role of vitamin in human body through the study of Raman spectrum.The five parts of this paper are as follows:1.we introduces the basic principle,basic character and application of Rarnan spectrum, We summarized the characteristics of SERS effect in the experiments,enhanced mechanism, applications and recent progress of surface enhanced Raman scattering. 2.The adsorption orientation and adsorption characteristics of vitamin M on silver sol were studied by FT-surface-enhanced Raman spectroscopy(FT-SERS) method with different pH change. The result shows that Vm adsorbed on the silver surfaces through carboxyl and nitrogen atoms.The adsorption of carboxyl on the silver surfaces is belonged to chemical adsorption.3.SERS spectra of VB2 absorbed on a silver colloid were measured with different concentrations and pH,the adsorption orientation and adsorption characteristics of VB2 on silver nanoparticles were studied.It is found that the intensity reaches to a maximum value as the concentration of VB2 is a 0.1 mmol/L;in the optimal pH of VB2 on silver sol is10.The interaction of VB2 with Ag nanoparticles is the physical and chemical adsorption by NH,Phenyl,which could also be effected by pH.4.NRS and surface enhanced Raman spectra(SERS) of Vitamin C on the silver colloidal substrate are recorded.Assignments of the Raman bands for VC molecules are presented.The adsorption orientation and adsorption characteristics were studied with different pH.According to the experiments,In SERS intense bands are observed at 1748,1651,1372,1256,562,446 and 149 cm^-1.The lactone ring of Vitamin C adsorbed on Ag sol has a tilted side on orientation.In addition, the free group of negative ion came into being as a result of charge transfer between O-H band of Vitamin C molecules and silver particles,and the C=O band was opened.5.The interaction of Vitamin B1(VB1) on silver colloid surface was studied by Fourier transformation surface-enhanced Raman spectroscopy(FT-SERS) in the presence of the halide ions (Cl^- Br^-,Ⅰ^-).The results show that the SERS intensities were decreased in sequence ofΓ,Br^-,and Cl^- while one was added to the VB1-silver colloid system.