Two-Dimensional Vibration Spectroscopy. V: Correlation of Mid- and near Infrared of Hard Red Winter and Spring Wheats

1996 ◽  
Vol 4 (1) ◽  
pp. 139-152 ◽  
Author(s):  
F.E. Barton ◽  
D.S. Himmelsbach ◽  
D.D. Archibald
Keyword(s):  
Raman Spectra ◽  
Spring Wheat ◽  
Near Infrared ◽  
Nir Spectroscopy ◽  
Correlation Spectroscopy ◽  
Analytical Models ◽  
Electromagnetic Spectrum ◽  
Two Dimensional ◽  
Stretching Vibrations ◽  
Agricultural Materials

Two-dimensional correlation spectroscopy across the near infrared (NIR) and mid-infrared (MIR) regions have been used to explain the NIR spectra of hard red winter and spring wheat and provide additional confidence in analytical models developed with empirical data. Recent studies have shown that the major C–H stretching vibrations and some of the aromatic C–H and ring stretching vibrations and the minor vibrations in the “fingerprint” region are correlated also. The technique has been expanded to include Raman spectra. The Raman spectra were enhanced with Maximum Likelihood methods to improve signal-to-noise (S/N) while maintaining resolution. This was necessary to eliminate the effects of fluorescence which degrades S/N. The use of NIR lasers at 1.1 μm generally eliminates fluorescence as a problem, but it is still quite prevalent in agricultural materials. The original study did not show any significant correlations to aromatic functionality. However, the band at 1552 nm correlates to the Raman and not to the MIR. This band has shown up in NIR spectroscopy models for the determination of lignin, but is not readily observed in the MIR. Thus it correlates to a Raman active rather than a MIR active band. The same phenomena are observed for the amide I, II and III bands for wheat. The interesting features from NIR and MIR are that there are correlations that distinguish winter from spring wheat. These, and the Raman spectra of wheat, will be shown. These studies show that multiple regions of the electromagnetic spectrum can be, and in deed need to be, used to interpret adequately the spectral and statistical results we have traditionally obtained in the NIR.

Rheo-Optical Near-Infrared (NIR) Characterization of Hydroxyl-Functionalized Polypropylene (PPOH)-Mesoporous Silica Nanocomposites Using Two-Trace Two-Dimensional (2T2D) Correlation Analysis

2019 ◽  
pp. 000370281986156 ◽  
Author(s):  
Ryota Watanabe ◽  
Hideaki Hagihara ◽  
Hiroaki Sato ◽  
Junji Mizukado ◽  
Hideyuki Shinzawa
Keyword(s):  
Mesoporous Silica ◽  
Near Infrared ◽  
Tensile Deformation ◽  
Nir Spectroscopy ◽  
Amorphous Region ◽  
Amorphous Structure ◽  
Correlation Spectroscopy ◽  
Two Dimensional ◽  
Correlation Peak ◽  
Thickness Change

A rheo-optical characterization technique based on the combination of near-infrared (NIR) spectroscopy and mechanical analysis was applied to the nanocomposite consisting of hydroxyl-functionalized polypropylene (PPOH) and mesoporous silica (MPS) to probe the deformation behavior. Substantial levels of spectral changes of NIR spectral features were captured when the polymer samples underwent tensile deformation. Sets of spectra were subjected to projection treatment to remove the effect of baseline fluctuations and thickness change inevitably caused by the tensile deformation of the sample. Then, two-trace two-dimensional (2T2D) correlation spectroscopy was applied to the pretreated spectra to elucidate spectroscopic signature associated with the difference between the initial and deformed samples. An asynchronous correlation peak appears between the bands at 1720 and 1700 nm respectively reflecting the contributions of predominantly amorphous and crystalline component of the PPOH, indicating the predominant variation of amorphous structure followed by that of crystalline structure. In addition, the predominant spectral change related to the amorphous band becomes even more acute by including the MPS with large pores. It is hence likely that the larger pore size of the MPS confines the more amorphous structure, which, in turn, causes simultaneous reorientation of the polymer chains in the amorphous region during the elastic deformation. Consequently, the incorporation of the MPS selectively restricts the deformation of the amorphous structure which eventually provides the obvious increase in the mechanical property of the PPOH polymer.

Two-Dimensional near Infrared Correlation Spectroscopy: Principle and its Applications

1998 ◽  
Vol 6 (1) ◽  
pp. 19-31 ◽  
Author(s):  
Yukihiro Ozaki ◽  
Yan Wang
Keyword(s):  
Correlation Analysis ◽  
Basic Principle ◽  
Near Infrared ◽  
Nir Spectroscopy ◽  
Correlation Spectroscopy ◽  
Mathematical Treatment ◽  
Two Dimensional ◽  
2D Correlation Spectroscopy

The basic principle and applications of generalised two-dimensional (2D) near infrared (NIR) correlation spectroscopy are reviewed in this paper. A brief history and the basic principle of 2D correlation spectroscopy are described first, and then its importance for NIR spectroscopy is discussed. An outline of the mathematical treatment of generalised 2D correlation spectroscopy is given. Several examples of generalised 2D NIR and 2D NIR-mid IR (MIR) heterospectral correlation analysis are introduced.

Identification of Overlapped Near-Infrared Bands of Glucose Anomers Using Two-Dimensional Near-Infrared and Middle-Infrared Correlation Spectroscopy

2002 ◽  
Vol 56 (7) ◽  
pp. 897-901 ◽  
Author(s):  
Aminiel Awichi ◽  
Eric M. Tee ◽  
Giri Srikanthan ◽  
Wei Zhao
Keyword(s):  
Mixed Mode ◽  
Near Infrared ◽  
Spectroscopic Method ◽  
Nir Spectroscopy ◽  
Correlation Spectroscopy ◽  
Two Dimensional ◽  
Combination Band ◽  
Spectral Changes ◽  
Glucose Anomers ◽  
Middle Infrared

Near-infrared (NIR) spectroscopy is a useful tool in determining glucose in biological matrices. Because α-anomers and β-anomers of glucose are in equilibrium in the solution, the observed NIR bands may come from the overlapping of vibrational modes of the anomers. We have conducted NIR and mid-infrared (MIR) absorption spectra measurements to determine the nature of the observed NIR features by using two-dimensional (2D) NIR and MIR correlation spectroscopy. The 2D NIR correlation spectra and 2D synchronous NIR and MIR correlation heterospectra are constructed based on the spectral changes of individual anomers upon mutarotation. We have identified a new NIR feature at 4350 cm−1 for the α-anomers and two new NIR features at 4200 and 4250 for the β-anomers. The 4350-cm−1 band of the α-anomers could be assigned to the combination band of C–H stretch at 2945 cm−1 and a mixed mode of C–H bending and O–H bending at 1415 cm−1. The 4200/4250-cm−1 bands of the β-anomers might be tentatively assigned to the combination band of C–H stretching at 2870 cm−1 and a mixed mode of C–H bending and O–H bending at 1315/1370 cm−1. This finding provides the spectral information needed for implementation of a highly selective coherent two-dimensional vibrational spectroscopic method, the DOVE-Raman four wave mixing for selective identification of glucose anomers from aqueous solutions.

Two-Dimensional Correlation of Fourier Transform Near-Infrared and Fourier Transform Raman Spectra I: Mixtures of Sugar and Protein

1996 ◽  
Vol 50 (4) ◽  
pp. 467-475 ◽  
Author(s):  
William Fred McClure ◽  
Hisashi Maeda ◽  
Jian Dong ◽  
Yongliang Liu ◽  
Yukihiro Ozaki
Keyword(s):  
Fourier Transform ◽  
Raman Spectrum ◽  
Raman Spectra ◽  
Cross Correlation ◽  
Near Infrared ◽  
Correlation Spectroscopy ◽  
Calibration Model ◽  
Two Dimensional ◽  
Data Point ◽  
Probable Origin

Two-dimensional (2D) correlation of near-infrared (NIR) and Raman spectra was carried out for mixtures of protein (lysozyme) and sugar (sucrose) to investigate the potential of this technique for qualitative NIR spectral interpretation. Cross-correlation by least-squares was employed to assess changes in both sets of spectra which result from changes in the set of sample spectra. Fourier transform (FT) NIR and NIR-excited FT-Raman spectra were measured for each of the samples under the same conditions, and point-for-point 2D cross-correlation was calculated. In this technique, each wavenumber in the NIR region gives rise to a sliced Raman spectrum where each data point is correlated to the NIR wavenumber, while each wavenumber in a Raman spectrum provides a sliced NIR spectrum in which each data point is correlated to the Raman wavenumber. For example, choosing NIR wavenumbers 7272, 6960, 6324, and 4812 cm−1 gives sliced Raman spectra with features attributable to sucrose, while choosing NIR wavenumbers at 8424, 5148, 5052, and 4584 cm−1 provides slices with distinct lysozyme features. Therefore, the technique permits the determination of the most probable origin of NIR signals by connecting NIR spectra, which have rather broad and overlapped bands, to Raman spectra consisting of sharp and clearly separated bands. It is also possible to produce sliced NIR spectra of lysozyme and sucrose by properly selecting wavenumbers in their Raman spectra. The NIR slices explain which wavenumbers in the NIR region are correlated to lysozyme or to sucrose. Thus, 2D correlation spectroscopy helps explain the reasons why certain wavenumbers are selected in a chemometric calibration model.

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