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Stray light analysis has great benefits in designing Raman spectrometry system, which is the sensitive detection system of weak optical signal. In this paper, optical design software and Solidworks are utilized to optimize the optical and mechanical structure. The system resolution is 0.7 nm, and the volume is 110 mm×95 mm, which belongs to portable and miniature Raman spectrometer. Based on the stray light simulation model, we made an analysis of ray tracing simulation for this system. First, the stray light come with the incident ray were suppressed by the aperture stop. Then the receiver of stray light was introduced and improved in the design progress to suppress internal stray light, especially for zero-order diffraction light of plane grating. The improved receiver of stray light is more effectively using the internal space of the spectrometer and analysis results show that a 50% reduction in the number of stray light and stray light normalized irradiance intensity from 10-5 down to 10-7. The analysis shows that the improved receiver of stray light can effectively suppress stray light, which is beneficial to weak signal detection, and provide reference for design and adjustment of the miniature Raman spectrometer.

In this paper, confocal Raman spectroscopy was applied to detect the contents of lead chrome green as a heavy-metal stain illegally added in tea. Firstly, Raman spectra of five different concentrations of lead chrome green in tea infusion were acquired based on specific concentration method. The qualitative analysis of sample added with lead chrome green was achieved with comparing the Raman spectra of sample and standard substance. Four main Raman characteristic wavenumbers, 1 341, 1 451, 1 527 and 1 593 cm(-1), were extracted for the qualitative identification of lead chrome green in tea. After spectral preprocessing of the raw Raman spectra, backward interval PLS (biPLS), competitive adaptive reweighted sampling (CARS) and successive projections algorithm (SPA) were combined to deeply mine the characteristic wavenumbers of lead chrome green in Raman spectra, and finally 14 characteristic wavenumbers were optimized. Partial least squares (PLS) and least square support vector machine (LS-SVM) were separately used to build the model based on the extracted 14 wavenumbers. As a result, these two models both had good robustness and high ability to predict and all the determination coefficient (R(2)) of calibration, validation and prediction were higher than 0.9, which proved the effectiveness of the extracted characteristic wavenumbers. Compared with the PLS model, the nonlinear model built by LS-SVM got a better result, R(2) of prediction was 0.964 and the root mean square error of prediction (RMSEP) was 0.535. This study indicated that it is feasible to detect the contents of lead chrome green illegally added in tea based on confocal Raman spectroscopy combined with specific sample treatment and chemometrics methods. This study helped the valid supervision of food safety problem on lead chrome green illegally added in tea.

Triphenyltin Chloride (TPhT) is one of the only two kinds of metal compounds known in the endocrine disruptors. TPhT is widely used in industry, agriculture and transportation fields, which can cause great impact on soil, marine and inland freshwater environment. This experiment collects the Raman signal of TPhT standard powders by applying laser confocal Raman spectroscopy to explore the feasibility of the method and to acquire optimized parameters. In this paper, we combined the application of laser confocal Raman spectroscopy with TPhT physical property. Due to different functional groups of TPhT molecules shows different vibration modes, the Raman spectra was divided into three wavenumber areas(1 500~3 200, 900~1 500 and 100~900 cm-1) to attribute and analyze their assignments of the Raman peaks, obtaining the characteristics of TPhT vibration modes and the corresponding characteristic peaks. Finally, a standard Raman spectra library was established with the spectral range between 100~3 200 cm-1. The results showed that the Raman spectra with high signal-to-noise ratio can be obtained in a short time when the laser power options decayed to 0.5% of the original power (500 mW) after 10s exposure and 2 times integration. Strong Raman signals observed in the Raman spectroscopy at 212, 332, 657, 997 and 1 577 cm-1 could be used as the characteristic peaks of TPhT in Raman detection. Otherwise, the co-occurrence of the Raman peaks at 657 and 997 cm-1 can be considered as the presence of TPhT in complex environmental samples. Experimental results are given to identify the presence of TPhT. The results would be used to identify the presence of TPhT residual in real environmental samples, which provide a theoretical basis and data base on Raman spectroscopy.

Early diagnosis have great positive effect on the treatment of gastric cancer patients. Raman spectroscopy can provide a useful monitor for hemoglobin dynamics. Besides, Raman spectroscopy has notable advantages in the fields of abnormal hemoglobin diagnosis, hemoglobin oxygen saturation deter mination and blood methemoglobin analysis. In this paper, novel silver colloid was synthesized by microwave heated method. The surface enhanced Raman spectrums of hemoglobin from 11 normal persons and 20 gastric cancer patients are measured and analyzed in order to obtain spectrums which are high repeatability and characteristic peaks protruding. By analyzing the assignations of the SERS bands, it found that the content of asparagine, tyrosine and phenylalanine in the hemoglobin are significantly lower than healthy people. Discussing the structure of hemoglobin, when hemoglobin combines with oxygen, Fe²⁺ is in a low spin state, ionic radius shrinks and moves 0. 075 nm and fall into the pore in the middle of the heme porphyrin ring plane. This spatial variation affects F8His connected with the iron, will narrow the gap between the globin in the two strands of the helix, as a result, HC2 tyrosine pushed out of the void. Using this mechanism, the absorption peak of 1 560 cm⁻¹ confirmed that the tyrosine content in patients with gastric cancer was lower than that of normal people. Principal component analysis(PCA) is employed to get a three-dimensional scatter plot of PC scores for the health and cancer groups, and it can be learned that they are distributed in separate areas. By using the method of discriminate analysis, it is found that the diagnostic algorithm separates the two groups with sensitivity of 90.0% and diagnostic specificity of 90.9%, the overall diagnostic accuracy was 90.3%. The results from this exploratory study demonstrate that, SERS detection of oxyhemoglobin combined with multivariate analysis would be an effective method for early diagnosis of gastric cancer.

Beta-carotene is an important kind of polyene biomolecules, which has significant applications on researching optoelectronic and functional materials. In-situ high pressure Raman spectra of beta-carotene are measured in CS2 solution and water respectively at pressure range from 0-0.60 GPa. Then we compared both of them the Raman shift and CC bond of the full width at half maximum (FWHM) of the Raman spectra. It is therefore concluded that both of the samples' Raman shift moved to the high wave number and the full width at half maximum increased depending of the pressure. The experiment phenomena were interpreted by the theory of "coherent weakly damped electronic-lattice vibration model" and "effective conjugation length model". The mechanism is that the beta-carotene is compressed and has the lower structure order, shorte the effective conjugation length, decreased Raman active, weaker the coherent weakly damping CC bond vibration in high pressure. Because of the CC bond length become short, so the Raman spectra are found to blueshift. The CC bond of the full width at half maximum (FWHM) of the Raman spectra increased is attributed to the increase of difference in C--C and C==C bond lengths. Moreover, due to dissolving in non-polar CS2 solvent, the beta-carotene encounters the interaction of the surrounding solvent molecules. So the dispersion force interaction between solute and solvent is more sensitive to pressure. Then it makes that the slop of Raman shift and the full width at half maximum in the CS2 solution are faster than dissolved in water with increasing pressure. This paper provides an application value for research on molecular structure change under the external field and the presence form of polyenes biomolecules in the solvent.

Identification and classification of microalgae are basis and premise in the study of physiological and biochemical characteristics for microalgae. Microalgae cells mainly consist of five kinds of biological molecules, including proteins, carbonhydrates, lipids, nucleic acids and pigments. These five kinds of biological molecules contents with different ratio in microalgae cells can be utilized to identify microalgae species as a supplement method. This paper investigated the application of Raman microspectroscopy technology in the field of rapid identification on different algae species such as aschlorella sp. and chlamydomonas sp. . Cultivated in the same conditions of culture medium, illumination duration and intensity, these two kinds of species of microalgae cells were immobilized by using agar, and then the samples were placed under 514. 5 nm Raman laser to collect Raman spectra of different growth periods of different species. An approach to remove fluorescence background in Raman spectra called Rolling Circle Filter (RCF) algorithm was adopted to remove the fluorescent background, and then some preprocessing methods were used to offset the baseline and smooth method of Savitzky-Golay was tried to make the spectra curves of total 80 samples smoother. Then 50 samples were randomly extracted from 80 samples for modeling, and the remaining 30 samples for independent validation. This paper adopted different pretreatment methods, and used the partial least squares (PLS) to establish model between the spectral data and the microalgae species, then compared the effects of different pretreatment methods. The results showed that with Raman microspectroscopy technology, the pretreatment method of max-peak ratio standardization was a more effective identification approach which utilizes the different content ratios of pigments of different microalgae species. This method could efficiently eliminate the influence on Raman signal due to different growth stages of microalgae and decomposition of pigments contents of microalgae in vivo. Compared with other traditional classification methods, this method had significant advantages like simpler procedure and shorter testing time, and it can also avoid some subjective measurement errors caused by unskilled operations. If the threshold was set to +/- 0.5, the prediction accuracy can reach 100%, and when the threshold was +/- 0.2, the prediction accuracy reached 86.67%, which proves the proposed new method can be a good approach to identify different algae varieties.

Surface-enhanced Raman spectroscopy (SERS) technique was used to analyze the Raman peaks of thiabendazole pesticides in the present paper. Surface enhanced substrates of silver nanoparticle were made based on microwave technology. Raman signals of thiabendazole were collected by laser Micro-Raman spectrometer with 514. 5 and 785 nm excitation wavelengths, respectively. The Raman peaks at different excitation wavelengths were analyzed and compared. The Raman peaks 782 and 1 012 at 785 nm excitation wavelength were stronger, which were C--H out-of-plane vibrations. While 1284, 1450 and 1592 cm(-1) at 514.5 nm excitation wavelength were stronger, which were vng and C==N stretching. The study results showed that the intensity of Raman peak and Raman shift at different excitation wavelengths were different And strong Raman signals were observed at 782, 1012, 1284, 1450 and 1592 cm(-1) at 514.5 and 785 nm excitation wavelengths. These characteristic vibrational modes are characteristic Raman peaks of carbendazim pesticide. The results can provide basis for the rapid screening of pesticide residue in agricultural products and food based on Raman spectrum.

Infrared spectroscopy (IR), the normal Raman spectroscopy (NRS) and the surface enhanced Raman spectroscopy (SERS) in new Ag/Cu nanomaterial of Rotundine were studied in the present paper. The IR and the NRS of Rotundine were calculated by the density functional theory (DFT) using B3LYP/6-311+G(d, p), then the spectral intensity graph of Rotundine were given. The vibrational peaks were assigned comprehensively by the visualization software of Gauss view 5. 0. Rotundine has obvious infrared and Raman vibrational peak in the wave number range of 3 300-2500 and 1 800-600 cm(-1). SnCl2 and PVP was used as capping agent for the silver nanoparticles in SERS of Rotundine. Finally, by using the method of cyclic immersion well dispersed silver nanoparticles was obtained and achieved good enhancement effect. This molecule acquired strong selective enhancement vibration peak, In the wave number ranges of 1 500-1 400 and 1 000-700 cm(-1) the enhancement effect is most obvious. After analyzed, the methylene of this molecule is adsorbed on the silver nanoparticles surface and the angle between the benzene ring and the silver substrate is close to 90 degrees. The theoretically calculated spectra of Rotundine are consistent with the obtained experimental spectra. There are some differences may be due to the interaction forces between molecules and so on. The visualization software displayed the structure characteristics and molecular group vibration of this molecular visually and provided important basis for assigning the vibrational peaks. Rotundine is an important traditional Chinese medicine agent contained in many kinds of sedative drugs. The study provides a strong basis for the rapid, feature and trace identification of Rotundine and also supplies important reference for the biological role of central inhibition of analgesic drugs.

In the present paper, a non-destructive, simple and rapid analytical method was proposed based on Raman spectroscopy (Raman) combined with principal component analysis (PCA) and support vector machine (SVM) as pattern recognition methods for adulteration of crude soybean oil (CSO). Based on fingerprint characteristics of Raman, the spectra of 28 CSOs, 46 refined edible oils (REOs) and 110 adulterated oil samples were analyzed and used for discrimination model establishment. The preprocessing methods include choosing spectral band of 780-1,800 cm(-1), Y-axis intensity correction, baseline correction and normalization in succession. After those series of spectral pretreatment, PCA was usually employed for extracting characteristic variables of all Raman spectral data and 7 principal components which were the highest contributions of all data were used as var- iables for SVM model. The SVM discrimination model was established by randomly picking 20 CSOs and 95 adulterated oils as calibration set, and 8 CSOs and 35 adulterated oils as validation set. There were 4 kinds of kernel function algorithm (linear, polynomial, RBF, sigmoid) respectively used for establishing SVM models and grid-search for optimization of parameters of all the SVM models. The classification results of 4 models were compared by their discrimination performances and the optimal SVM model was based on linear kernel classification algorithm with 100% accuracy rate of calibration set recognition, a zero misjudgment rate and the lowest detection limit of 2.5%. The above results showed that Raman combined PCA-SVM could discriminate CSO adulteration with refined edible oils. Since Raman spectroscopy is simple, rapid, non-destructive, environment friendly, and suitable for field testing, it will provide an alternative method for edible oil adulteration analysis.

Through computation, this paper obtained Aflatoxin B1 and its trans-isomer molecules stable structure which was rarely reported by the density functional theory(DFT) with B3LYP complex function and 6-311 + g(d, p) basis set. Through a single point calculations and geometry analysis, we know that the cis-structure is more stable than trans-structure. On the basis of this, Raman spectra of two molecules are calculated by the same method and basis set. compared with the Aflatoxin B1 cis-structure powder experimental Raman spectra, it was informed that numerical results with experimental results combined with a better. While 1582, 3065, 1626 means to take the strongest of the three peaks of cis-structure raman characteristics, 1616, 3065, 1659 cm(-1) is indicated for the strongest of the three peaks of trans-structure raman characteristics. Use the Hirshfeld atom division method combined with Multiwfn software to analyze the composition of frontier orbital based on optimization calculation, and it was informed that the electrophilic ability of two monlecules was stronger than the nucleophilic ability. The proportion of C1 atoms in LUMO orbital are respectively 21.48 percent, 20.62 percent by calculating, thus it is predicted that C1 atom is most main position spot depriving of the electronic in DNA to cause cancer. The above-mentioned research has certain theoretical directive significance in detection, transformation and toxicity inhibition of the cis-trans isomers.

The present paper proposed for the first time the flocculation-filtration method for separation of interfering substances in milk, such as fat. In this method only two steps were carried out. Firstly, aluminum chloride (PAC, Al2 (OH)nCl6-n,) is used to flocculate the milk; Secondly, water filter was used to filter the mixture. Then the clear filtrate could be used for the detection of melamine. The whole preprocessing would not take more than one minute. The pretreatment process was optimized. Experiments show that the adding proportion of PAC should be about 2%-3% for best filtration efficiency, and that it would have the best flocculation effect when the mixture was mildly alkaline. High performance liquid chromatography experiments show that the melamine recovery of this method is more than 90%. Samples pretreated by the flocculation--filtration method were clearer and the baselines of spectral curve obtained by sensitizing Raman method were more smooth which means better purification compared to those samples pretreated by centrifugal pretreatment method. The pretreatment method proposed can be used in HPLC and Raman spectroscopy methods for rapid detecting melamine in liquid milk. This method shows better separation effect, simpler operation, and lower time and money cost than those pretreatment processes in the existing standard melamine detection method for milk. By use of this pretreatment method, the melamine rapid detection efficiency would be greatly improved.

Hemoglobin plays many significant biological roles in organism. However, our knowledge about its structure and function is not enough to meet the demand of clinical diagnosis. Raman spectroscopy has been shown to be an attractive optical technique which can provide direct access to the structure and function of hemoglobin. It is a proven tool for elucidating structural information of hemes and other vicinal groups. Furthermore, it can provide a useful monitor for hemoglobin dynamics. Besides, Raman spectroscopy has notable advantages in the fields of abnormal hemoglobin diagnosis, hemoglobin oxygen saturation determination and blood methemoglobin analysis. The present paper reviews the research on hemoglobin structure and function using Raman spectroscopy and the application in hemoglobinopathy diagnosis. In addition, we discuss the factors affecting the measurement in Raman spectroscopy of hemoglobin. The aim of the review is to promote the application of Raman spectroscopy to the research of hemoglobin structure and function.

The Raman spectrums of hemoglobin from 20 normal persons and 21 esophageal cancer patients were measured and analyzed in the present paper, the results show obvious differences between the Raman spectrums of esophageal cancer patients and normal persons. Compared with normal persons, there are more iron ions in low spin state and less in high spin state in the hemoglobin of esophageal cancer patients. It indicates that some iron ions in high spin state turned to low spin state because of cancerization, and this experimental result coincides with the fact that hemolysis is more likely to occur in cancer patients. Principal component analysis (PCA) was employed to get a three-dimensional scatter plot of PC scores for the health and cancer groups, and it can be learned that they are distributed in separate areas. By using the method of discriminate analysis, it was found that the diagnostic algorithm separates the two groups with sensitivity of 90.5% and diagnostic specificity of 95%, and the overall diagnostic accuracy was 92.7%. The results from this exploratory study demonstrate that Raman spectroscopy combined with multivariate analysis would be an effective method for early diagnosis of esophageal cancer.

For the purpose of the rapid prediction of saturated fatty acid, oleic acid, linoleic acid content in edible vegetable oil, the Raman spectra of a batch of edible vegetable oils and their one-one mixtures with different ratios were measured in the range of 800-2 000 cm(-1), 91 samples were measured totally in this research, the obtained Raman spectra data were preprocessed by a new method proposed in this paper called auto-set fulcrums baseline fitting method based on peak-seeking algorithm, and 8 characteristic peak values (872 cm(-1) [v(C-C)], 972 cm(-1) [delta(C=C) trans], 1 082 cm(-1) [v(C-C)], 1 267 cm(-1) [delta(=C-H) cis], 1 303 cm(-1) [delta(CH2) twisting], 1 442 cm(-1) [delta(CH2) scissoring], 1 658 cm(-1) [v(C=C) cis], 1 748 cm(-1) [v(C=O)]) were extracted to be the eigenvalues for the whole spectra, among the 8 peaks there are three peaks (972, 1 267, 1 658 cm(-1)) that play an important role in the establishment of mathematical model, they are closely concerned with C=C band which distinguishes the three fatty acid types. By using these eigenvalues as inputs, and actual saturated fatty acid, oleic acid, linoleic acid contents of sample oils as outputs, a prediction mathematical model that predicts simultaneously the three fatty acid contents was established using multiple regression analysis: multi-output least squares support vector regression machine (MLS-SVR) and partial least squares (PLS). Results show that the MLS-SVR has better effects. The predicting results are compared with results of gas chromatography(GC), and the obtained root mean square error of prediction(RMSEP) for saturated fatty acid, oleic acid, linoleic acid are 0.496 7%, 0.840 0% and 1.019 9%, and the correlation coefficients (r) are 0.813 3, 0.999 2 and 0.998 1, respectively. When this model is applied in the detection of new unknown oil samples, the prediction error does not exceed 5%. Results show that the Raman spectra analysis technology based on MLS-SVR can be a convenient, fast, non-destructive, and precise new method for oil detection.

Traditional pesticide residue detection methods are usually complicated, time-consuming, and destructive. Rapid, nondestructive, online real-time is the development direction of the pesticide testing. In the present paper, we use surface enhanced Raman spectroscopy (SERS) technique to detect the organophosphorus pesticide residue of phorate and fenthion on apple to investigate a fast, nondestructive detection method for the pesticide of phorate and tiguron on apples. The results show that the characteristic frequencies of the two organophosphorus pesticides are easier to identify using surface-enhanced Raman spectroscopy. We select Raman signal at 728 cm(-1) for phorate and that at 1 512 cm(-1) for fenthion as target peak for quantitative analysis, and use an internal standard to establish phorate and fenthion linear regression model. This method can be used as a quantitative analysis reference of phorate and fenthion.

In the present paper, silver colloid films prepared by self-assembly method were used as surface-enhanced Raman scattering (SERS) active substrates to achieve trace detection of antibiotics in water. Silver colloids were prepared using the microwave heating method, and silver colloids films were prepared with self-assembly method. The enhancement of sliver colloid films to antibiotics was analysed by changing the pH value of silver colloid and times of films. Significant effects of pH value on silver colloid films were observed. And the silver colloid films with five times, prepared by silver colloids with pH 4 had the best enhancement factor. They were used as SERS active substrates to detect three antibiotics (chloramphenicol, ciprofloxacin, enrofloxacin). The experimental limits of detection were 120, 15, 120 nmol x L(-1), respectively. These results show that such substrate has a very high sensitivity and application value, and might be able to be used for trace detection of antibiotics in aquiculture.

The vitamin B12 molecule has long fascinated chemists because of its exclusive complex structure and unusual reactivities in biological systems. In order to achieve a better understanding of the structural attribute of the Vitamin B12 molecule when it interacted with metal, in the present paper, the vitamin B12 molecules adsorbed on variation of copper electrode potential from 0 to -1.0 V was studied by surface-enhanced Raman spectroscopy (SERS). An excellent SERS substrate was obtained with insitu electrochemical oxidation-reduction cycle (ORC), and its surface roughness was characterized by atomic force microscope (AFM). Assignments of Raman peaks observed by normal Raman spectrum (NRS) and SERS spectra of vitamin B12 molecule were given based on previous literatures. It was found that the potential-dependent relative intensity changed in SERS spectra which depended on the vitamin B12 molecular orientation with respect to the copper surface according to the surface selection rule (SSR). It was concluded that the corrin ring was adsorbed in tilt form on copper surface and the Co-CN group was farther away from the copper surface at higher potentials. With the decrease in potential, the tilt angle between the corrin ring and copper surface became smaller, then the Co-N group and 5,6 dimethylbenzimidazole group got close to the copper surface. The results offered an important structural attribute of vitamin B12 molecule when it interacted with copper electrode for the first time, and supplied a meaningful reference for the electrochemical bioactivity of the vitamin B12 molecule.

In the present paper, studies on in-situ Raman spectra at high pressure up to 12.85 Gpa were performed on beta-carotene using a diamond anvil cell (DAC), and the effects of pressure on the characteristic peaks and pi-electron delocalization of beta-carotene were discussed. The results showed that Raman frequencies of the main characteristic peaks of beta-carotene shifted to high wavenumber with the increase in pressure. The relation between pressure and the three main characteristic peaks of beta-carotene was given as follows: nu1, (C==C) = 4. 74P + 1511.4, w (C-C) = 2.55P + 157.6 and nu3 (CH3) = 2.25P + 1011.3. Under the pressure of 5.38 GPa, Raman spectrum of nu1 + nu2 sum frequency of beta-carotene was subjected to cleavage. Fuethermore, the degree of relectron decolization was reduced with the increase in pressure, leading to C==C double bond more compressible than C-C bond on the main chain of beta-carotene.

Due to the deficiency of energy supply and negative environmental impacts. Much attentions have been paid to agnicultural these lignocellulosic the replacement of fossil resources with and forestry biomass for the production of bio-fuels, chemicals and biomaterials on a global scale. Highly effective utilization of biomass is dependent on full understanding of their chemical composition and structural characteristics. A state-of-the-art Raman spectroscopy has evolved an important and nondestructive technique for plant research as information concerning histochemistry and structural characteristics of plant cell walls can be investigated in a nearly native state. In this paper, the principle of Raman imaging was introduced briefly. Meanwhile, the research progress in structural analysis of major components, micro-area distribution and molecular organization of the cellulose and lignin in the plant cell walls by Raman spectroscopy was summarized. The aim of the review is to promote the application of Raman spectroscopy to the study of plant cell walls.

It is generally accepted that Raman spectroscopy is an advanced method with simple operation, small amount of specimens needed as well as rapid on-line screening, detection and identification. However, in the technology of determination, sample preparation is also an significant factor during analysis process. It would affect the accuracy and precision of the results, and normally involved complicated procedure. Developing a rapid and effective sample preparation method coupled with Raman detective technology is a method worth study. In the present paper, the simply basic principle, the origin and development of generating Raman spectra were introduced, some Raman technology, such as the surface-enhanced Raman spectroscopy, tip-enhanced Raman spectroscopy, shell-isolated nanoparticle enhanced Raman spectroscopy and the sample preparation were discussed.

Raman spectroscopy technique could satisfy industrial field measurement requirements because of the advantages of rapidity and nondestructiveness. Thus, It has been widely used in a variety of quantitative and qualitative analysis fields. The volume ration of alcohol and water in alcoholic beverages, i. e. the ethanol content, is a key factor in the detection of the quality of wine products. The development of the detection system for quick, easy and real-time ethanol content measurement is of great significance for national production. In the present paper, net signal analysis method (NAS) was used in the ethanol content quantitative analysis of Raman spectra from the ethanol aqueous solution. The linear regression model was developed between the net signal of ethanol and its concentration. The results showed that the qualitative analysis method based on net signal analysis was superior to the traditional linear regression method such as the MLR method based on the feature peak intensity and the PLS model. It not only improved the prediction accuracy of the model but also enhanced the robustness of the model. Because the model established by the NAS-MLR method is simple and stable, it is possible to develop the portable measurement instruments in future.

In the present paper, four kinds of cluster analysis methods were used in rapid, non-destructive discrimination of hypoglycemic tablets by the Raman spectroscopy technology. Nine kinds of hypoglycemic tablets, including 48 samples, were determined using a Raman spectrometer. The sample data were pretreated with the methods of frequency range cutting, baseline correction, smoothing and vector normalization, then were analyzed by K-means, hierachical cluster, self-organizing maps (SOM) and PCA-SOM respectively. The results demonstrated that SOM was better than K-means and hierachical cluster, and it provided the best discrimination when combined with PCA. The research offers a new approach to the rapid discrimination of different kinds of hypoglycemic tablets.

The authors made a theoretical analysis and experiment research on the relation of time-resolved coherent anti-Stokes Raman scattering (T-CARS) intensity and the sample concentrations in this paper. It was proved experimentally that the T-CARS intensity is quadratic at the concentration higher than 35%, but is linear with the sample concentration at the concentration lower than 20%, which fits with theoretical analysis. And the research results correct inaccurate previous perceptions, which is conducive to better interpretation and application of the CARS process. The linear relation between the intensity of the CARS with the sample concentration at low concentrations indicates that the CARS is allowed for direct and precise concentration measurements, therefore it will be of great importance in biology and biochemistry.

In the present paper, B3LYP (Becke's three-parameter hybrid method with the Lee, Yang, and Parr gradient corrected correlation functional) and HF (Hartree-Fock) methods at 6-31+G* * (C, H, N, O)/LANL2DZ(Ag) level were used to optimize molecular configurations of thymine. Base on the optimized structure, the normal Raman spectrum (NRS) of thymine and the surface-enhanced Raman spectrum (SERS) of thymine adsorbed on Ag and Ag2 were calculated, which were compared with the experimental values. The calculation results indicated that the result of the DFT for NRS was more approximate to the ever reported experimental date than those of HF results. A better conformity of SERS was found between the HF computed and the experimental results. At the end, detailed analysis of the Raman spectrum and more comprehensive assignments of the vibration mode for thymine were studied by the software of GaussView.

In the present paper, taking Tiegunyin tea as an example, surface enhanced Raman scattering (SERS) spectrum of tea was obtained, the effects of different active substrates were explored from the aspects of enhanced factor, background noise, repeatability, and signal to noise ratio (SNR), while the impact of adsorption time on the measurement was also discussed. The results show that it is feasible to obtain the SERS spectrum of tea, and Raman signal of SERS spectrum was greatly enhanced compared with that of regular Raman spectrum. The active substrate of silver colloid prepared by the reduction of silver nitrate and trisodium citrate has a better enhanced effect, while different adsorption times have no direct influences on the SERS measurement. The method based on SERS firstly proposed in this paper may provide an alternative method for the discriminant analysis and quality identification of tea.

Raman spectroscopy is an analytical techniques based on Raman scattering, which gives information of molecular vibration and rotation. Raman spectroscopy has been widely employed in the investigations of the structure of biomolacules, because it has many advantages over the common chemical analysis. Raman spectroscopy is non-destructive to the samples. Moreover, it requires simple sample preparation and small sample amount. Raman spectroscopy can be used not only for fast detections of damages of biological macromolecules, such as proteins, nucleic acids and lipids, but also for diagnosis and surgical treatments of cancer. By comparing the Raman spectra of normal tissue and cancer tissue, the differences in the characteristic absorption peaks between the two kinds of tissues can be confirmed, which provides significant information for final diagnosis of cancer and determination of the resection extent of tumor. This paper reviewed the researches on biomolecular damages by Raman spectral inspections. It described the applications of Raman spectral techniques, such as surface-enhanced Raman spectroscopy, Fourier transform Raman and UV resonance Raman spectroscopy, in the detection of protein secondary structures, membrane lipids and DNA damages. A prospect of the development of Raman spectroscopy in the future was given.

In the present paper, a method was established based on laser tweezer Raman spectroscopy for rapid quantification of astaxanthin in Phaffia rhodozyma cells. First, the Raman spectra of astaxanthin standard solution with different concentrations were determined and the standard curve for astaxanthin with the peak intensity at 1 520 cm- was plotted; And then the Phaffia yeast cells cultivated in different nitrogen source and carbon source medium were divided into two parts, one for the detection of Raman spectra, and the other for the determination of ultraviolet visible spectrophotometry; Finally the relationship between the two methods was analyzed. The correlation coefficient of standard curve for astaxanthin is 0.998 3. Comparing laser tweezers Raman spectroscopy method with traditional ultraviolet visible spectrophotometry in analyzing the content of astaxanthin in unit mass Phaffia rhodozyma and the yield of astaxanthin in unit volume fermentation broth of Phaffia rhodozyma, the authors found that the data obtained have good linear relationship. And the correlation coefficients are 0.917 7 and 0.905 4, respectively. Therefore, both methods have almost the same effect of measuement. But laser tweezers Raman spectroscopy method is more efficient in the quantitative analysis of astaxanthin in Phaffia rhodozyma cells.

Surface enhanced Raman spectroscopy (SERS) has shown the advantage of detecting low concentration biofluids presently. Saliva SERS of 21 lung cancer patients and 22 normal people were measured and differentiated in the present paper. Intensities of most peaks of lung cancer patients are weaker than that of normal people, while some stronger but with a small change rate. Those peaks were assigned to proteins and nucleic acids which indicate a corresponding decrease of those substances in saliva. Principal component analysis (PCA) and linear discriminant analysis (LDA) were used to deduce and discriminate the two groups of data, resulting in accuracy, sensitivity, and specificity being 84%, 94%, and 81%, respectively.

Malachite green isothiocyanate (MGITC) is a Raman probe molecule that was applied to cells detection, tissue composition detection and cells stain imaging. In the present work, MGITC molecular structure was optimized by density functional theory(DFT) calculation. MGITC molecular Raman spectra and infrared spectra were calculated with Hartree-Fork theory and MP2 theory based on STO-3G level, then two theoretical Raman spectra were carefully compared with experimental spectra, and good agreements were obtained between the theoretical and experimental results. MGITC structure parameters were given also in the paper including bond lengths and bond angles etc. Vibrational modes were assigned to all bands in the range between 550 and 4 200 cm(-1). This work will facilitate the application of MGITC Raman probe for biology.

The present paper reports the FT-infrared spectra and FT-Raman spectra of the S-thyminyl-L-cysteine. The optimal concentration of the S-thyminyl-L-cysteine on silver sol is 10(-4) mol L(-1). The interaction of S-thyminyl-L-cysteine with Ag nanoparticles was adsorbed by COO-, NH3+, S, and ring in the tilted way. Amino peak was enhanced in the acidic condition, carboxyl peak was enhanced in alkaline condition. Adsorption of S-thyminyl-L-cysteine on silver nanoparticles was mainly with carboxyl under the acidic condition and with amino under the alkaline condition. Other groups had no change at different pH. Establishment of this adsorption model provided important information and useful reference for further Raman spectra study of PNA, peptides and other biological molecules.

To study the spectrum processing methods for Raman microscopy on single living cell and develop the pre-process techniques for Raman spectrum of single living cell to enhance the signal to noise ratio, sensitivity, and decrease the fluorescence influence, wiping off the cosmic rays was used to improve the spectrum. The spectra classification, spectra average and filtration were applied to enhance signal to noise ratio. The fluorescence was depressed for quantity analysis or utilized for analysis by comparing the background and the spectra. Results show that (1) comparing the spectra with short exposure time and more scans can wipe off the cosmic rays effectively. (2) the spectra classification, spectra average and filtration can improve the quality of spectra and can show some weak and sensitive bands. (3) sometimes the fluorescence has useful information. It is concluded that the proposed techniques for Raman spectrum of single cell in this paper can show the sensitive and weak intensity peaks and reflect the information of molecules structures very well.

Labelled immunoassay by surface enhanced Raman scattering (SERS) has great research and application value. It combines SERS which has the high sensitivity and high selectivity with specific adsorption in immunology. The present paper mainly studies the regeneration about SERS labelled immunoassay, striving to develop the recycling value of it. The authors used glycine-HCl eluent for the sandwich structure including solid matrix antibody, antigen and labelled immuno-gold colloids, then the authors had got expected result. The complex of antibody and antigen would be separated by changing the pH scale. It could elute the most antigen and the labelled immuno-gold colloids. Also the authors could assemble it again and distinguish the characteristic SERS spectrum of the reporter molecules. Under this condition, we researched the stability and reusing of this technology. The authors found that it has better stability and it retained activity after 10 recycles of applications.

In the present paper, five different kinds of hypoglycemic tablets were identified using kernel principal component analysis (KPCA)-clustering analysis of their Raman spectra. KPCA was used to compress thousands of spectral data into several variables and to describe the body of the spectra before clustering analysis was chosen as further research method. The results showed that hypoglycemic tablets could be quickly classified using KPCA-clustering analysis. A disadvantage of Raman spectroscopy for this type of analysis is that it is primarily a surface technique. As a consequence, the spectra of the tablet core and its coating might differ. However, the KPCA-clustering analysis turned out to be a sufficiently reliable discrimination, i. e., 96% of the hypoglycemic tablets with coating and 100% of the hypoglycemic tablets without coating were predicted correctly. Overall, the Raman spectroscopic method in the present paper plays a good role in the identification and offers a new approach to the rapid discrimination of different kinds of hypoglycemic tablets.

The authors have found that by virtue of utilizing the interaction of strongly chemically adsorbed SnCl2 with the analytes of organic/biologic molecules, the authors can not only effectively eliminate the laser carbonization and oxidation of probe molecules (e. g. pyridine), but also obtain specially enhanced Raman signals (e. g. vitamin B6). This method is applicable to the SERS spectroscopic analysis of highly reactive organic/biologic molecules. In the present paper, the authors report the investigation results on the electrochemical SERS spectra of L-carnosine (LCar) for the first time, mainly concentrating on the influence of adsorbed SnCl2 and applied potential on the SERS spectra of LCar. The SERS spectra of LCar were badly interfered by laser carbonization in the absence of SnCl2. However, in the presence of SnCl2 high quality SERS spectra of LCar could be obtained free of carbonization. It is demonstrated that LCar can be immobilized on the gold substrate indirectly via surface coordination with the pre-adsorbed SnCl2 under potential control. Apparently, such a sandwich-like adsorption configuration as Au-Sn(II)-LCar is beneficial both to sensing the strong electromagnetic field at the nanostructured gold surface and to preventing the LCar from damage by the laser.

Monkey cerebral cortex, an important part in the brain to control action and thought activities, is mainly composed of grey matter and nerve cell. In the present paper, the in situ Raman spectra of the cerebral cortex of the birth, teenage and aged monkeys were achieved for the first time. The results show that the Raman spectra for the different age monkey cerebral cortex exhibit most obvious changes in the regions of 1000-1400 and 2800-3000 cm(-1). With monkey growing up, the relative intensities of the Raman bands at 1313 and 2885 cm(-1) mainly assigned to CH2 chain vibrational mode of lipid become stronger and stronger whereas the relative intensities of the Raman bands at 1338 and 2932 cm(-1) mainly assigned to CH3 chain vibrational mode of protein become weaker and weaker. In addition, the two new Raman bands at 1296 and 2850 cm(-1) are only observed in the aged monkey cerebral cortex, therefore, the two bands can be considered as a character or "marker" to differentiate the caducity degree with monkey growth In order to further explore the changes, the relative intensity ratios of the Raman band at 1313 cm(-1) to that at 1338 cm(-1) and the Raman band at 2885 cm(-1) to that at 2 932 cm(-1), I1313/I1338 and I2885/I2932, which are the lipid-to-protein ratios, are introduced to denote the degree of the lipid content. The results show that the relative intensity ratios increase significantly with monkey growth, namely, the lipid content in the cerebral cortex increases greatly with monkey growth. So, the authors can deduce that the overmuch lipid is an important cause to induce the caducity. Therefore, the results will be a powerful assistance and valuable parameter to study the order of life growth and diagnose diseases.

Raman spectrum is an important and effective method for the study of biological molecules in water. Measuring the Raman spectra for biological molecules in water, however, is very difficult because of the small Raman scattering cross section and the high electronic excitation energy of water molecules. In the present paper, the authors applied both technologies of liquid-core optical fiber and the resonance Raman spectra, then the intensity of Raman spectra was enhanced to a great extent. In this experiment, we chose the laser wavelength 514.5 of Ar+ ion laser as excitation laser, because we could obtain the maximal intensity of resonance Raman spectra at this wavelength. The experiment results show that, for the trace inspecting study of beta-carotene biological molecules in water, the concentration in the range of 10(-7)-10(-9) mol x L(-1) can be detected by quartz liquid-core optical fiber and the concentration in the range of 10(-9)-10(-10) mol x L(-1) by Teflon liquid-core optical fiber. The detecting utmost will be further reduced if improving the quality of optical fiber.

In the present paper, the fluorescence spectra of three common pesticides, isoprocarb, metolcarb and pirimicarb, were theoretically studied. The geometries of these compounds were fully optimized by density function theory (DFT) method at the B3LYP/6-31+G level. The three compounds under study were confirmed as true minima on the potential energy surface in the presence of only real frequencies by the vibrational analysis. The fluorescence spectra were calculated by configuration interaction (CI) method with PCM model, and the results match with the experimental values. The results of calculation suggest that the three compounds with planar structures are hyperconjugation systems. By the addition of the donor-electron groups, the wavelengths of the fluorescence spectra increased, and the frequencies underwent red-shift. In addition, the substitute alkyl has no more influence on the fluorescence spectra, but the addition of amido groups has more influence on the fluorescence spectra.

Luxiancao is a new medicine for liver cancer, and is purely natural botanical It has good curative effects and few side effects. The curative mechanism of Luxiancao is unknown. In the present paper, the authors used a 514. 5 nm laser to measure the changes in the Raman spectrum of liver cancer cells (SMMC-7721) treated by Luxiancao at different concentrations. The study can help us know more about the mechanism, efficiency and side effects of Luxiancao. The results show that significant changes were observed in the cells' Raman spectra after reacting with Luxiancao. The intensities at 785 and 1 092 cm(-1), corresponding to DNA phosphate backbone vibration, were reduced; and the Raman bands for the bases A and G at 1 312 and 1585 cm(-1) also decreased, indicating that Luxiancao may be inserted in DNA bases and influence the DNA replications, resulting in the reduction in DNA content and breaking of the DNA strands. Besides, the intensity of 1 360 cm(-1), belonging to Trp, decreased gradually and disappeared in the end, indicating the Trp of cancer cells began to be exposed when adding in Luxiancao. The bands at 1 004 cm(-1) for Phe and 1 656 cm(-1) for proteins alpha-helix also decreased, suggesting that there were changes in the structure of protein and circumstance of amino acid. Moreover, the effects on cancer cells were enhanced gradually with the HCPT concentration increasing. Since a Raman spectrum is a chemical fingerprint of a sample, the different concentration dependent changes in the Raman spectra of individual cells due to reacting with Luxiancao can overcome the limitations of other detection systems used for quantitative and qualitative analysis of the drug.

The surface enhanced Raman scattering (SERS) of L-phenylalanine solution system was studied in the present paper. The enhancement effect is obvious. Compared to the conventional Raman spectra of solid phenylalanine, the frequency deviations of some peaks in the SERS spectra were observed, and the relative strengths of some peaks were certainly changed. The influence of three different laser sources on the intensity of SERS spectra is discussed. The 514.42 nm of laser source is the best among the 514.42, 632.81 and 785.18 nm. The intensity of SERS spectra can be changed with the concentration of L-phenylalanine. It does not benefit the formation of SERS spectra when the concentration is too high or too low. When the concentration of bottom solution is 1 x 10(-3) mol x L(-1), the enhancement effect of SERS is the strongest. The pH value of system also has obvious effect on the SERS, and when the pH value is 8, the enhancement effect of SERS is the best. It is the total influence of the pH on the coacervation of the silver sol and existent form of the phenylalanine.

The gastric cancer cell and normal cell were comparatively detected by means of laser Raman spectrum in the present paper. The special Raman spectrum wave crest of gastric cancer cell was inquired. It was found that the special Raman spectrum wave crest of gastric cancer cell differs from the one of normal cell. After the sample at concentration of 1.25 x 10(5) individual x mL(-1) was cultivated for several days, a few special Raman spectrum wave crests of sample at 583, 633 and 656 nm respectively were detected. This is a few new special Raman spectrum wave crests rarely reported. Whether at the special Raman spectrum wave crests or at the same several Raman spectrum wave crests 674, 707, 773 and 799 nm for both canner cell and normal cell, the Raman spectrum intensity increases with the cancer cell concentration. As a result, the laser Raman spectrum analyse is considered truly a kind of rapid and effectual method to check cancer cell.

In the present paper we report quantitative analysis of glucose using internal standard laser Raman spectra. A good linear correlation was observed between the intensities of the -COO band at 1 125 cm(-1) using excition wavelength of 632.81 nm (r = 0.998 8) and the glucose concentration over the range 0-1.8 mol x L(-1). Band intensities were normalized against an internal standard (water band at 1 643 cm(-1)), and the limit of detection (L. O. D.) of glucose is 0.022 7 mol x L(-1). The interference ions would not influence the quantitative analysis. When this method was used to determine 5% glucose NaCl, 5% glucose, and 10% glucose injections, the result showed that the recoveries are 71.88%-126.31%, 81.02%-124.89% and 74.87%-121.32%, and the RSDs are 5.44%, 4.34% and 0.94%, respectively. The non destructive, non intrusive nature of the method makes internal standard laser Raman spectra a convenient, accurate, and green quantitative analysis method.

The vibrational spectra of thymine were predicted by density functional theory (DFT). In the calculation B3LYP complex function, and diffuse function and polarization function were added to heavy atoms and light atoms. Taking the effects of H-bonds into consideration, the authors added two water molecules in our calculation and simulated the case of forming H-bonds in crystal thymine. Whilst the Raman and infrared spectra of thymine were recorded, and the spectra of thymine calculated from DFT agree with the experimental results. The calculation results in the present paper are more approximate to the experimental data than ever reported. The vibrational modes of thymine were assigned.

The present paper investigates Raman spectral characters of liquid glycerin by the experiment at the pressure of 0-1.0 GPa and the temperature of 29 degrees C, and defines the relation between the pressure and the Raman peak of glycerin at ambient temperature. The result shows that there are two characteristic Raman peaks of glycerin defined as v(CH) and v(CH2), and both of them move to higher positions as system pressure increases. The relation between the system pressure and peak positions of glycerin is given as the following: v(CH) = 0.0092P + 2886.67 and v(CH2) = 0.009 4P + 2948.53. On the other hand, glycerin is reliable as a liquid pressure gauge for high pressure experiment. The equation applied to demarcate system pressure is also showed: P = 106.4 v(CH2) - 3.14 x 10(5).

This paper introduces the structure and the feature of moissanite anvil cell, which is composed of moissanite anvil, supporting and creating pressure system, heater system and metal gasket. Because of its high hardness, high heat conductance, low thermal expansion, good thermal stability and low price, moissanite is a good material of anvil for high-temperature and high-pressure experimental studies. With this cell, the Raman spectrum of sodium carbonate solution, sodium sulfate solution and distilled water has been in situ measured under high-temperature and high-pressure. With increasing pressure, it can be observed that the 1066 cm(-1) Raman modes of sodium carbonate solution and the 982 cm(-1) Raman modes of sodium sulfate solution shift to high wave numbers obviously. With increasing temperature, the frequency at maximum intensity shifts to high wave numbers, the full width at half-maximum intensity decreases in the Raman spectrum of water.

In this paper, the Raman and difference FTIR spectra of NTO crystal, NTO solutions at different pH and saturated aqueous solution of Rb(NTO) x H2O have been studied. The determined structure of crystal suggests that the metal ion with oxygen and nitrogen atoms of [chemical structure see text] C-N, [chemical structure see text] C-NO2, [chemical structure see text] C=O and H2O formed bonds. The highest characterization peaks of Raman and FTIR spectra show that [chemical structure see text] C-NO2, [chemical structure see text] C=O and [chemical structure see text] C-N of NTO- formed week coordination bonds. The vibration spectra of saturation solution basically accord with those of the crystal. The bonds of saturation solution of the coordination compound have not changed. Therefore, the different vibration spectra of the saturation water solution of Rb (NTO) x H2O can be explicated by the formation of the bonds in crystal. The coordination compound formation mechanism of metal ion with NTO in alkali aqueous solution is discussed.

This paper studies Raman spectra of methanol atpressures from 169.2 MPa up to 713.8 MPa and at ambient temperature. The result shows that the spectral profile of stretching vibrational modes of CH and OH gradually changes and Raman shift moves to higher and lower frequency respectively with increasing pressure, which indicates that the energy of C-H bonding increases with pressure, and the influence of hydrogen bonding on O-H function group is greater than that of pressure. In addition, the relative peak area of O-H stretch band decreases with pressure, showing that the total intensity of O-H bonding is weaker compared with C-H bonding.

The applications of the high sensitivity of Surface-Enhanced Raman Spectroscopy (SERS) in labeled immunoassay have proved to be very useful. In the sandwich structure of "immobile antibody-antigen-labeled antibody", the authors prepared the labeled antibody by attaching gold nanoparticles, which was first labeled with molecule that had SERS signal, to the antibody. In this article, colloids were labeled with Raman reporter thiophenol through S-Au bond on gold and formed surface-enhanced Raman scattering (SERS) reporter-labeled gold colloids. Then, goat anti-rat antibody was adsorbed onto the reporter-labeled gold colloids and formed reporter-labeled immunogold colloids. This paper studied factors affecting FT-SERS reporter-labeled immunogold colloids such as the sizes of gold particles, the amount of thiophenol in gold colloids and processing time, and whether goat anti-rat antibody would influence the SERS of reporter-labeled gold colloids.

In this paper, the authors obtained Raman spectra of DNA in fiber and aqueous solution at different temperatures. These spectra revealed that the vibration of bases and phosphate group were influenced by varying temperature. Adenine was the most sensitive to varying temperature in all of the vibrational modes. The wave numbers of most of the vibrational modes decreased as the temperature increased except for the band at 1101 cm(-1), and the shift of wave numbers mainly concentrated upon the beginning point of denaturation at 70 degrees C. The temperature dependence of Raman intensity was discussed, and two peaks were obtained at 38 and 82 degrees C, respectively. The results obtained by Raman spectra were in agreement with experimental data by DSC at 82 degrees C. The peak at 38 degrees C was related to the biological activity region of DNA function.

In this paper, Fourier transform infrared spectroscopy (FTIR) was used to identify edible mushrooms belonging to Auriculariales, Aphyllophorales, and Agaricales of Basidiomycotina. Vibrational spectra of fruiting bodies of ten species belonging to nine different genera of mushrooms (one is cultivated, and the others are wild growing) were recorded. The spectra were divided into five regions, i.e. 3 050 to 2 800 cm(-1), 1 750 to 1 500 cm(-1), 1 500 to 1 200 cm(-1), 1 200 to 950 cm(-1), and 950 to 700 cm(-1). These regions contain characteristic bands among different mushrooms. According to the characteristic bands in the five regions, different species of mushrooms can be identified. Vibrational spectra in the interval between 950 and 700 cm(-1) could serve as fingerprints to discriminate different genera of mushrooms.

Stable and good quality of Surface-Enhanced Raman Scattering (SERS) signal from net rhodium electrode in the ultraviolet region was observed for the first time by our group recently. In this paper, both qualitative and quantitative analyses are given to interpret the new experimental results mainly based on the electromagnetic field theory. The mechanisms of SERS for rhodium electrode in the ultraviolet region are mainly attributed to the lightning rod effect together with the weak surface plasmon resonance. According to the calculation, the surface-averaged enhancement factor (SEF) for rhodium electrode in the ultraviolet region is about two orders of magnitude when the surface of the substrate is roughened properly, which is in good agreement with the experimental results. The authors also give a comparative study to show why silver, which is the best SERS active substrate in the visible and near infrared region, can't give any SERS signal when the 325 nm excitation line is used.