scholarly journals High-Wavenumber Raman Analysis

2021 ◽  
Author(s):  
Shan Yang
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Near Infrared ◽  
Inorganic Material ◽  
Fluorescent Proteins ◽  
Biological Tissues ◽  
Hydrogen Atoms ◽  
Raman Analysis ◽  
Fingerprint Region ◽  
Nir Laser

Raman spectra are molecule specific, and their peaks in the fingerprint region (200-2000 cm−1) are often sufficient for material identification. High-wavenumber signals (> 2000 cm−1) are rare in inorganic material but rich in organic materials containing light hydrogen atoms. Reports on high-wavenumber (HW) Raman signals are far less than fingerprint signals. This could be partially attributed to the difficulty obtaining HW Raman signals, especially from biological materials containing fluorescent proteins. The development and the availability of InGaAs array and the near-infrared (NIR) laser enabled the acquisition of distinct HW Raman from bio-materials. In this chapter, we will introduce recent applications of HW Raman spectroscopy on different materials, especially on biological tissues. Raman instrumentation based on multiple lasers or multiple spectrometers will also be discussed.

scholarly journals Applications of Vibrational Spectroscopy for Analysis of Connective Tissues

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 922
Author(s):  
William Querido ◽  
Shital Kandel ◽  
Nancy Pleshko
Keyword(s):  
Raman Spectroscopy ◽  
Vibrational Spectroscopy ◽  
Near Infrared ◽  
Ex Vivo ◽  
Biological Tissues ◽  
Label Free ◽  
Connective Tissues ◽  
Bone Properties ◽  
Composition And Structure

Advances in vibrational spectroscopy have propelled new insights into the molecular composition and structure of biological tissues. In this review, we discuss common modalities and techniques of vibrational spectroscopy, and present key examples to illustrate how they have been applied to enrich the assessment of connective tissues. In particular, we focus on applications of Fourier transform infrared (FTIR), near infrared (NIR) and Raman spectroscopy to assess cartilage and bone properties. We present strengths and limitations of each approach and discuss how the combination of spectrometers with microscopes (hyperspectral imaging) and fiber optic probes have greatly advanced their biomedical applications. We show how these modalities may be used to evaluate virtually any type of sample (ex vivo, in situ or in vivo) and how “spectral fingerprints” can be interpreted to quantify outcomes related to tissue composition and quality. We highlight the unparalleled advantage of vibrational spectroscopy as a label-free and often nondestructive approach to assess properties of the extracellular matrix (ECM) associated with normal, developing, aging, pathological and treated tissues. We believe this review will assist readers not only in better understanding applications of FTIR, NIR and Raman spectroscopy, but also in implementing these approaches for their own research projects.

Potential of Near-Infrared Fourier Transform Raman Spectroscopy in Food Analysis

1992 ◽  
Vol 46 (10) ◽  
pp. 1503-1507 ◽  
Author(s):  
Y. Ozaki ◽  
R. Cho ◽  
K. Ikegaya ◽  
S. Muraishi ◽  
K. Kawauchi
Keyword(s):  
Raman Spectroscopy ◽  
Fourier Transform ◽  
Fatty Acid ◽  
Raman Spectra ◽  
Food Analysis ◽  
Near Infrared ◽  
Egg White ◽  
Ft Raman Spectroscopy ◽  
Ft Raman

The 1064-nm excited Fourier transform (FT) Raman spectra have been measured in situ for various foods in order to investigate the potential of near-infrared (NIR) FT-Raman spectroscopy in food analysis. It is demonstrated here that NIR FT-Raman spectroscopy is a very powerful technique for (1) detecting selectively the trace components in foodstuffs, (2) estimating the degree of unsaturation of fatty acids included in foods, (3) investigating the structure of food components, and (4) monitoring changes in the quality of foods. Carotenoids included in foods give two intense bands near 1530 and 1160 cm−1 via the pre-resonance Raman effect in the NIR FT-Raman spectra, and therefore, the NIR FT-Raman technique can be employed to detect them nondestructively. Foods consisting largely of lipids such as oils, tallow, and butter show bands near 1658 and 1443 cm−1 due to C=C stretching modes of cis unsaturated fatty acid parts and CH2 scissoring modes of saturated fatty acid parts, respectively. It has been found that there is a linear correlation for various kinds of lipid-containing foods between the iodine value (number) and the intensity ratio of two bands at 1658 and 1443 cm−1 ( I1658/ I1443), indicating that the ratio can be used as a practical indicator for estimating the unsaturation level of a wide range of lipid-containing foods. A comparison of the Raman spectra of raw and boiled egg white shows that the amide I band shifts from 1666 to 1677 cm−1 and the intensity of the amide III band at 1275 cm−1 decreases upon boiling. These observations indicate that most α-helix structure changes into unordered structure in the proteins constituting egg white upon boiling. The NIR FT-Raman spectrum of old-leaf (about one year old) Japanese tea has been compared with that of its new leaf. The intensity ratio of two bands at 1529 and 1446 cm−1 ( I1529/ I1446), assignable to carotenoid and proteins, respectively, is considerably smaller in the former than in the latter, indicating that the ratio is useful for monitoring the changes in the quality of Japanese tea.

scholarly journals 785 nm Raman Spectroscopy of CVD Diamond Films

2007 ◽  
Vol 1039 ◽  
Author(s):  
Paul William May ◽  
James A Smith ◽  
Keith N Rosser
Keyword(s):  
Raman Spectroscopy ◽  
Film Thickness ◽  
Raman Spectra ◽  
Relative Intensity ◽  
Near Infrared ◽  
Diamond Films ◽  
Polycrystalline Diamond ◽  
Cvd Diamond ◽  
Raman Study ◽  
Thin Polycrystalline

AbstractRaman spectroscopy is a powerful technique often used to study CVD diamond films, however, very little work has been reported for the Raman study of CVD diamond films using near infrared (785 nm) excitation. Here, we report that when using 785 nm excitation, the Raman spectra from thin polycrystalline diamond films exhibit a multitude of peaks (over 30) ranging from 400-3000 cm−1. These features are too sharp to be photoluminescence, and are a function of film thickness. For films >30 μm thick, freestanding films, and for films grown in diamond substrates the Raman peaks disappear, suggesting that the laser is probing the disordered small-grained interface between the diamond and substrate. Some of the peaks change in relative intensity with time (‘blinking’), and the spectra are very sensitive to position on the substrate – this is reminiscent of the behaviour seen in SERS spectra.

scholarly journals Fusion of Near-Infrared and Raman Spectroscopy for In-Line Measurement of Component Content of Molten Polymer Blends

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3463 ◽  
Author(s):  
Shichao Zhu ◽  
Zhuoming Song ◽  
Shengyu Shi ◽  
Mengmeng Wang ◽  
Gang Jin
Keyword(s):  
Raman Spectroscopy ◽  
Data Fusion ◽  
Polymer Blends ◽  
Raman Spectra ◽  
Near Infrared ◽  
Molten Polymer ◽  
Low Level ◽  
Line Measurement ◽  
Component Content ◽  
Level Fusion

Spectral measurement techniques, such as the near-infrared (NIR) and Raman spectroscopy, have been intensively researched. Nevertheless, even today, these techniques are still sparsely applied in industry due to their unpredictable and unstable measurements. This paper put forward two data fusion strategies (low-level and mid-level fusion) for combining the NIR and Raman spectra to generate fusion spectra or fusion characteristics in order to improve the in-line measurement precision of component content of molten polymer blends. Subsequently, the fusion value was applied to modeling. For evaluating the response of different models to data fusion strategy, partial least squares (PLS) regression, artificial neural network (ANN), and extreme learning machine (ELM) were applied to the modeling of four kinds of spectral data (NIR, Raman, low-level fused data, and mid-level fused data). A system simultaneously acquiring in-line NIR and Raman spectra was built, and the polypropylene/polystyrene (PP/PS) blends, which had different grades and covered different compounding percentages of PP, were prepared for use as a case study. The results show that data fusion strategies improve the ANN and ELM model. In particular, mid-level fusion enables the in-line measurement of component content of molten polymer blends to become more accurate and robust.

scholarly journals Detection of Age-Related Changes in Tendon Molecular Composition by Raman Spectroscopy—Potential for Rapid, Non-Invasive Assessment of Susceptibility to Injury

2020 ◽  
Vol 21 (6) ◽  
pp. 2150
Author(s):  
Nai-Hao Yin ◽  
Anthony W. Parker ◽  
Pavel Matousek ◽  
Helen L. Birch
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Flexor Tendon ◽  
Biological Tissues ◽  
Ring Structure ◽  
Total N ◽  
Non Invasive ◽  
Age Related ◽  
Superficial Digital Flexor Tendon

The lack of clinical detection tools at the molecular level hinders our progression in preventing age-related tendon pathologies. Raman spectroscopy can rapidly and non-invasively detect tissue molecular compositions and has great potential for in vivo applications. In biological tissues, a highly fluorescent background masks the Raman spectral features and is usually removed during data processing, but including this background could help age differentiation since fluorescence level in tendons increases with age. Therefore, we conducted a stepwise analysis of fluorescence and Raman combined spectra for better understanding of the chemical differences between young and old tendons. Spectra were collected from random locations of vacuum-dried young and old equine tendon samples (superficial digital flexor tendon (SDFT) and deep digital flexor tendon (DDFT), total n = 15) under identical instrumental settings. The fluorescence-Raman spectra showed an increase in old tendons as expected. Normalising the fluorescence-Raman spectra further indicated a potential change in intra-tendinous fluorophores as tendon ages. After fluorescence removal, the pure Raman spectra demonstrated between-group differences in CH2 bending (1450 cm−1) and various ring-structure and carbohydrate-associated bands (1000–1100 cm−1), possibly relating to a decline in cellular numbers and an accumulation of advanced glycation end products in old tendons. These results demonstrated that Raman spectroscopy can successfully detect age-related tendon molecular differences.

scholarly journals Quantitative Evaluation of Acetaminophen in Oral Solutions by Dispersive Raman Spectroscopy for Quality Control

2012 ◽  
Vol 27 ◽  
pp. 215-228 ◽  
Author(s):  
Viviane G. Borio ◽  
Rubens Vinha ◽  
Renata A. Nicolau ◽  
Hueder Paulo M. de Oliveira ◽  
Carlos J. de Lima ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Quality Control ◽  
Pharmaceutical Industry ◽  
Raman Spectra ◽  
Near Infrared ◽  
Calibration Model ◽  
Fiber Optic Probe ◽  
Analytical Methodology ◽  
Gold Standard Method ◽  
Optic Probe

This work used dispersive Raman spectroscopy to evaluate acetaminophen in commercially available formulations as an analytical methodology for quality control in the pharmaceutical industry. Raman spectra were collected using a near-infrared dispersive Raman spectrometer (830 nm, 50 mW, 20 s exposure time) coupled to a fiber optic probe. Solutions of acetaminophen diluted in excipient (70 to 120% of the commercial concentration of 200 mg/mL) were used to develop a calibration model based on partial least squares (PLSs) applied to Raman spectra of solutions and, subsequently, obtain linearity, accuracy, precision (repeatability), and sensitivity of the method using the near-infrared spectroscopy (NIRS) as a gold standard method. This model was used to predict the acetaminophen concentration in commercial samples from different lots of acetaminophen formulations (200 mg/mL) with a PLS-prediction error of about 0.6%. Commercial medicines had PLS predicted concentrations errors below 2.5%, whereas NIRS had an error of about 3.7% compared to the label concentration. It has been demonstrated the applicability of Raman spectroscopy with fiber probe for quality control in pharmaceutical industry of commercial formulations.

Basis set dependence using DFT/B3LYP calculations to model the Raman spectrum of thymine

2016 ◽  
Vol 14 (01) ◽  
pp. 1650002 ◽  
Author(s):  
Jakub Bielecki ◽  
Ewelina Lipiec
Keyword(s):  
Raman Spectroscopy ◽  
Ionizing Radiation ◽  
Raman Spectra ◽  
Density Functional ◽  
Surface Enhanced Raman Spectroscopy ◽  
Basis Set ◽  
Basis Sets ◽  
Hydrogen Atoms ◽  
Additional Layer ◽  
Tip Enhanced Raman Spectroscopy

Raman spectroscopy (including surface enhanced Raman spectroscopy (SERS) and tip enhanced Raman spectroscopy (TERS)) is a highly promising experimental method for investigations of biomolecule damage induced by ionizing radiation. However, proper interpretation of changes in experimental spectra for complex systems is often difficult or impossible, thus Raman spectra calculations based on density functional theory (DFT) provide an invaluable tool as an additional layer of understanding of underlying processes. There are many works that address the problem of basis set dependence for energy and bond length consideration, nevertheless there is still lack of consistent research on basis set influence on Raman spectra intensities for biomolecules. This study fills this gap by investigating of the influence of basis set choice for the interpretation of Raman spectra of the thymine molecule calculated using the DFT/B3LYP framework and comparing these results with experimental spectra. Among 19 selected Pople’s basis sets, the best agreement was achieved using 6-31[Formula: see text](d,p), 6-31[Formula: see text](d,p) and 6-11[Formula: see text]G(d,p) sets. Adding diffuse functions or polarized functions for small basis set or use of a medium or large basis set without diffuse or polarized functions is not sufficient to reproduce Raman intensities correctly. The introduction of the diffuse functions ([Formula: see text]) on hydrogen atoms is not necessary for gas phase calculations. This work serves as a benchmark for further research on the interaction of ionizing radiation with DNA molecules by means of ab initio calculations and Raman spectroscopy. Moreover, this work provides a set of new scaling factors for Raman spectra calculation in the framework of DFT/B3LYP method.

Characterization of Raman Spectra Measured in Vivo for the Detection of Cervical Dysplasia

2007 ◽  
Vol 61 (9) ◽  
pp. 986-993 ◽  
Author(s):  
Amy Robichaux-Viehoever ◽  
Elizabeth Kanter ◽  
Heidi Shappell ◽  
Dean Billheimer ◽  
Howard Jones ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Sensitivity And Specificity ◽  
Near Infrared ◽  
Squamous Metaplasia ◽  
Cervical Dysplasia ◽  
High Grade Dysplasia ◽  
Measured Signal ◽  
High Grade

Raman spectroscopy has been shown to have the potential for providing differential diagnosis in the cervix with high sensitivity and specificity in previous studies. The research presented here further evaluates the potential of near-infrared Raman spectroscopy to detect cervical dysplasia in a clinical setting. Using a portable system, Raman spectra were collected from the cervix of 79 patients using clinically feasible integration times (5 seconds on most patients). Multiple Raman measurements were taken from colposcopically normal and abnormal areas prior to the excision of tissue. Data were processed to extract Raman spectra from measured signal, which includes fluorescence and noise. The resulting spectra were correlated with the corresponding histopathologic diagnosis to determine empirical differences between different diagnostic categories. Using histology as the gold standard, logistic regression discrimination algorithms were developed to distinguish between normal ectocervix, squamous metaplasia, and high-grade dysplasia using independent training and validation sets of data. An unbiased estimate of the accuracy of the model indicates that Raman spectroscopy can distinguish between high-grade dysplasia and benign tissue with sensitivity of 89% and specificity of 81%, while colposcopy in expert hands was able to discriminate with a sensitivity and specificity of 87% and 72%.

Nondestructive Discrimination of Biological Materials by Near-Infrared Fourier Transform Raman Spectroscopy and Chemometrics: Discrimination among Hard and Soft Ivories of African Elephants and Mammoth Tusks and Prediction of Specific Gravity of the Ivories

1997 ◽  
Vol 51 (8) ◽  
pp. 1154-1158 ◽  
Author(s):  
Masahiko Shimoyama ◽  
Hisashi Maeda ◽  
Hidetoshi Sato ◽  
Toshio Ninomiya ◽  
Yukihiro Ozaki
Keyword(s):  
Raman Spectroscopy ◽  
Fourier Transform ◽  
Specific Gravity ◽  
Raman Spectra ◽  
Near Infrared ◽  
Principal Component ◽  
Biological Materials ◽  
Calibration Model ◽  
Fourier Transform Raman Spectroscopy ◽  
Ft Raman

This paper demonstrates the usefulness of near-infrared (NIR) Fourier transform (FT) Raman spectroscopy and chemometrics in nondestructive discrimination of biological materials. The discrimination among three kinds of materials—hard ivories, soft ivories, and mammoth tusks—has been investigated as an example. NIR (1064-nm) excited FT-Raman spectra were measured in situ for these materials, and principal component analysis (PCA) of the obtained spectra was carried out over the 1800–400-cm−1 region. The two kinds of ivories are clearly discriminated from one another on the basis of a one-factor plot. It was found that treatment of the Raman data by multiplicative scatter correction (MSC) greatly improves the ability to discriminate. Principal component weight loadings show that the discrimination relies upon the ratio of collagen and hydroxyapatite included in two kinds of ivories. The discrimination among the hard and soft ivories and mammoth tusks was made by a three-factor plot for FT-Raman spectra after the MSC treatments. Partial least-squares regression (PLSR) enabled us to make a calibration model which predicts the specific gravity of the hard and soft ivories.

Near-Infrared Raman Spectroscopy Using CCD Detection and a Semiconductor Bandgap Filter for Rayleigh Line Rejection

1992 ◽  
Vol 46 (6) ◽  
pp. 891-893 ◽  
Author(s):  
Alfons Schulte
Keyword(s):  
Raman Spectroscopy ◽  
Fourier Transform ◽  
Raman Spectra ◽  
Near Infrared ◽  
Sapphire Laser ◽  
Laser Line ◽  
Rayleigh Line ◽  
Rejection Filter ◽  
Multichannel Detection ◽  
Fourier Transform Raman

A novel application of a tuneable Ti: sapphire laser and a CdTe Rayleigh line rejection filter for near-infrared Raman spectroscopy employing a single grating spectrograph and multichannel detection is demonstrated. Raman spectra of liquid, solid, and photobiological samples have been measured within 75 cm−1 of the exciting laser line. At excitation wavelengths between 790 and 850 nm, a significant improvement in sensitivity over that for present Fourier transform Raman techniques has been obtained.

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