| Raman and infrared spectra belong to the category of molecular vibration spectra, to some extent, both of them have complementary relationship, but it shows there is essential difference in generating mechanism, which is as follows:for incident light, Raman spectra is derived from scattering effect of molecular, and infrared spectra is due to the absorption of molecular. In recent decades, Raman and infrared spectra have been widely used as spectroscopy analysis method, and meanwhile it gradually develop some related spectroscopy technology of detection. Laser tweezers Raman spectroscopy (LTRS) is a optical technology that combined optical trap technique with Micro-Raman spectroscopy, using a beam to trap suspension cell and excite the Raman scattering of molecule, not only eliminating adverse effects caused by common micro-Raman technique because cells must fix on slide, but also obtaining a higher signal noise ratio, so the LTRS is an effective method to study molecular structures of living cells, and serves a popular tool of single-cell molecular level at present. As we know, Infrared spectroscopy has been developed a mature tool, due to rapid, accurate and nondestructive advantages, so it has been widely applied in qualitative and quantitative analysis of herbal quality. In the paper, laser Raman tweezers-based analysis carotenoids synthesis and the application of Chinese herbal identification using infrared spectroscopy are mainly introduced, and detailed content are as follows:In this thesis there are eight chapters. Chapter I:"The view of laser Raman spectra and carotenoids", a brief introduction about Raman spectra, LTRS, Raman spectra data processing method, overview and historical background in research of carotenoids, respectively.Chapter II "Using Raman tweezers optimization fermentation medium of generating carotenoids in Rhodotorula glutinis cell ", the results indicated that carotenoid content were obviously different for different medium. Furthermore, we showed the high correlation between UV analysis and Raman peak height data. It is noteworthy that quantitative analysis of Raman peak height suggested the appropriate nitrogen and carbon resource were yeast extract+tryptone and glucose.ChapterⅢ" Monitoring and rapid quantification of total carotenoids in Rhodotorula glutinis cells using laser tweezers Raman spectroscopy", in the chapter, we monitored dynamic process of carotenogensis in Rhodotorula glutinis cell at different time points, and reveal accumulation rule and synthesis mechanism of carotenoids. The data showed that the accumulation of carotenoids and lipids occurred mainly in the late exponential and stationary phases when the cell growth was inhibited by nutrient limitation. Meanwhile, the carotenoid concentration changed together with the concentration of nucleic acids, which increased in the first phase and decreased in the last phase of the culture. These data demonstrate that LTRS is a rapid, convenient and reliable method to study the carotenogenesis process in vivo.Chaper IV " The separation and identification of carotenoids ", firstly, carotenoids was extracted by ultrasonic, then we applied thin layer chromatography technique to separate carotenoids, finally the pigments were identified by using UV-Visible spectra and Raman spectra, the results were as follows, the thin layer chromatography was able to separate pigments successfully, which had the advantages of simple, quick, moreover,we could aslo draw a preliminary conclusion that there were at least three kinds of pigments in Rhodotorula glutinis cell, one kind wasβ-carotene, the rest might be torulene and torularhodin. After the scan of UV-Visible light and detection of Raman Spectroscopy, the UV-V scan results showed thatβ-carotene had the maximum absorption at the wavelength of 450 nm, and the torulene pigment was located at 496 nm and 525 nm respectively, however, the maximum absorption of torularhodin was responsible for 495 nm. The Raman spectra of three pigments were analysed, we found that the peak location (C=C) based on three pigments were different, due to different composition molecular structure, in addition, the content of torulene and torularhodin had a larger proportion in carotenoids mixture, at last, the ratios of Raman peak height were also different, but which could be used as a indicator for identifying different pigments quantitatively in future.Chapter V:the overviews of infrared spectroscopy technology. The chaper describes the basic principle of infrared spectra, Fourier transform infrared spectrometer, samples preparation technologies and the research advances of infrared spectroscopy in the field of Chinese herbal. Chapter V:Identification of Cortex Phellodendri by Fourier-Transform Infrared Spectroscopy and Principal Component Analysis, the chapter demonstrated that the application of infrared spectroscopy combined with PCA might be used as a tool to discriminate the herbal Cortex Phellodendri rapidly and undamagedly. The satisfying classification model obtained from PCA proved that the identification of Cortex Phellodendri from the six regions was basically achieved; besides, to some extent, the sparse density of the samples distribution reflected the genetic relationship. The loading factors of the model were analyzed, and the results indicated that the differences between Cortex Phellodendri samples mostly depended on the contents of protein, carbohydrates, lipids, alkaloids, sterols, obaculactone, oba-cunone, obacunonlc acid.Chapter VII:Assessment of Polygonum Multiflorum based on different origins by infrared spectra and chemometrics. In the chapter, the principal component analysis model was constructed identify samples from four different origins, according to the model, the first three principal components accounted for 98% of the variance information, and each sample was able to form distinct cluster in the principal component space, then the identification of Polygonum multiflorum from the four regions was basically achieved. The loading factors of the model were analyzed, and the results indicated that the differences between Polygonum multiflorum samples mostly depended on the contents of aromatic compounds, calcium oxalate, phospholipids, glycoprotein, polysaccharides and glycosides. Finally, soft independent modeling of class analogy was applied to predict unknown samples, and the recognition rate of blind samples was up to 100%. On the whole, combined with chemometrics, infrared spectroscopy provides an effective way to assess Polygonum multiflorum rapidly and undamagedly.Chapter VIII:Conclusions and prospect. Summarizes this study, point out the significance and lacking, look into the future of this work. |
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