| Raman spectrum belongs to molecular spectrum. Because the vibration and rotation of molecule can induce change of Raman shift, Raman intensity and shape of Raman band, the study of Raman spectrum can provide information of molecular structure, so we can do research in druggery detection, trace analysis and vibrational spectrum investigation of molecules through the study of Raman spectrum. With the expansion of frequency range of modern laser and the enrichment of light detection method, sensitivity of Raman spectrum has made great progress. Combined with other analytic methods such as IR, EELS, AES, XPS, SEM, TEM, AFM, SNOM, MS, CS, etc., Raman spectrum is sure to have a broader field of application.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. Surface-Enhanced Raman Scattering(SERS) is a new technique of Raman spectrum which can greatly enhance Raman intensity. This technique has reached the level of monolayer detection and was applied as a main investigation method of molecular structure in our experiment.This thesis consists of four parts. In the first part, we gave an introduction of SERS, the advantages of Raman spectrum and status of SERS research were discussed. We summarized the characteristics of SERS effect in experiment and described the mechanisms of SERS and theoretic models of it. It's an accepted view that themechanism of electromagnetic enhancement and the mechanism of chemical enhancement are both in existence. But which one is more important in different experiment, specific condition must be accounted for.In the second part, we investigated the active substrates of SERS and introduced the instruments in experiment and the preparation of samples. Because Raman intensity is related to activity of substrate in experiment, we summarized active substrates of SERS which were often employed in experiment, and then we described the preparation of active substrates in detail, we also discussed how to judge activity of substrates in the end.In the third part, we did research in vitamin k3 by SERS. Assignments of the Raman band for vitamin k3 molecules were presented for the first time. We concluded that a strong interaction lied between Vitamin K3 molecules and silver surface through analyzing the information of molecular structure. Finally, we explained the experimental results by the model of charge transfer and verified identification of vibrational mode of vitamin k3 molecules. We accomplished the first step of SERS research for vitamin k3 molecules. Our research provided information for the application of SERS techniques in druggery detection and trace analysis.In the fourth part, we did research in vitamin C by SERS, and then we accounted for application of Raman spectrum by quantitative analysis of Conjugated Polymer/Single-Walled Carbon Nanotubes. Assignments of the Raman band of vitamin C molecules were presented for the first time and some conclusions about vitamin C molecules were drawn. We accomplished the first step of SERS research of vitamin C molecules. In addition, we discussed the rule of quantitative analysis by the integral result to Raman spectrum of Conjugated Polymer/Single-Walled Carbon Nanotubes... |
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