Search results for "Fourier transform infrared spectra"
showing 3 items of 3 documents
The infrared and Raman spectra of solid tridehydropeptides : influence of ΔAla and ΔPhe on the spectral profile
2012
Abstract A series of solid tripeptides Boc-Gly-X-Gly-OMe (X = dehydroalanine (ΔAla), dehydrophenylalanine (ΔPhe)) was investigated by Raman scattering and Fourier transform infrared spectra to examine the conformational marker bands of the unsaturated residue. The observed fundamental modes gave us the opportunity to analyze structural features that change due to the substitution of Ala by ΔAla and due to the different spatial arrangement of ΔPhe ( Z and E isomers). In addition, we showed the alteration of the spectral profile when the large size residue (Phe) is introduced into the backbone of the peptide with ΔPhe (in Boc-Gly-Δ (Z) Phe-Phe-OMe). The frequency ranges of interest included t…
Global frequency and intensity analysis of the / / / band system of 12 C 2 H 4 at 10 μm using the D 2h Top Data System
2016
Abstract A global frequency and intensity analysis of the infrared tetrad of 12C2H4 located in the 600 – 1500 cm − 1 region was carried out using the tensorial formalism developed in Dijon for X2Y4 asymmetric-top molecules. It relied on spectroscopic information available in the literature and retrieved from high-resolution Fourier transform infrared spectra recorded in Brussels in the frame of either the present or previous work. In particular, 645 and 131 line intensities have been respectively measured for the weak ν10 and ν4 bands. Including the Coriolis interactions affecting the upper vibrational levels 101, 71, 41 and 121, a total of 10 757 line positions and 1645 line intensities ha…
Classification of Pecorino cheeses produced in Italy according to their ripening time and manufacturing technique using Fourier transform infrared sp…
2010
Fourier-transform infrared spectroscopy, followed by linear discriminant analysis of the spectral data, was used to classify Italian Pecorino cheeses according to their ripening time and manufacturing technique. The Fourier transform infrared spectra of the cheeses were divided into 18 regions and the normalized absorbance peak areas within these regions were used as predictors. Linear discriminant analysis models were constructed to classify Pecorino cheeses according to different ripening stages (hard and semi-hard) or according to their manufacturing technique (fossa and nonfossa cheeses). An excellent resolution was achieved according to both ripening time and manufacturing technique. A…