scholarly journals Hydrogen Bonding and Solvation of a Proline-Based Peptide Model in Salt Solutions

Life ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 824
Author(s):  
Sara Catalini ◽  
Barbara Rossi ◽  
Mariagrazia Tortora ◽  
Paolo Foggi ◽  
Alessandro Gessini ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Resonance Raman Spectroscopy ◽  
Conformational Stability ◽  
Solvation Shell ◽  
Hydrogen Bond Interaction ◽  
Relevant Role ◽  
Multi Wavelength ◽  
Sensitivity And Selectivity ◽  
Uv Resonance Raman Spectroscopy ◽  
Water Salt

The hydrogen bonding of water and water/salt mixtures around the proline-based tripeptide model glycyl-l-prolyl-glycinamide·HCl (GPG-NH2) is investigated here by multi-wavelength UV resonance Raman spectroscopy (UVRR) to clarify the role of ion–peptide interactions in affecting the conformational stability of this peptide. The unique sensitivity and selectivity of the UVRR technique allow us to efficiently probe the hydrogen bond interaction between water molecules and proline residues in different solvation conditions, along with its influence on trans to cis isomerism in the hydrated tripeptide. The spectroscopic data suggest a relevant role played by the cations in altering the solvation shell at the carbonyl site of proline., while the fluoride and chloride anions were found to promote the establishment of the strongest interactions on the C=O site of proline. This latter effect is reflected in the greater stabilization of the trans conformers of the tripeptide in the presence of these specific ions. The molecular view provided by UVRR experiments was complemented by the results of circular dichroism (CD) measurements that show a strong structural stabilizing effect on the β-turn motif of GPG-NH2 observed in the presence of KF as a co-solute.

Automated Detection of Fingerprint Traces of High Explosives Using Ultraviolet Raman Spectroscopy

2009 ◽  
Vol 63 (5) ◽  
pp. 559-563 ◽  
Author(s):  
Peter Jander ◽  
Reinhard Noll
Keyword(s):  
Raman Spectroscopy ◽  
Resonance Raman Spectroscopy ◽  
Roc Curves ◽  
Automated Detection ◽  
Operating Characteristics ◽  
Blind Test ◽  
Sample Spectrum ◽  
Real World Applications ◽  
Sensitivity And Selectivity ◽  
Uv Resonance Raman Spectroscopy

Ultraviolet (UV) resonance Raman spectroscopy is a promising technique for the detection of trace explosives. For real-world applications, it is necessary to develop data evaluation algorithms that automatically recognize the spectral features of explosives in a sample spectrum. We have developed a robust algorithm that can tolerate high levels of fluorescence background. We successfully demonstrated the detection of traces of ANFO and TNT explosives at surface coverage levels of 55 μg/cm2 in a blind test experiment. The sensitivity and selectivity is discussed in terms of receiver operating characteristics (ROC) curves.

UV resonance Raman spectroscopic study of photodegradation of hardwood and softwood lignins by UV laser

Holzforschung ◽  
2008 ◽  
Vol 62 (2) ◽  
pp. 183-188 ◽  
Author(s):  
Krishna K. Pandey ◽  
Tapani Vuorinen
Keyword(s):  
Lignin Degradation ◽  
Laser Energy ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Photochemical Degradation ◽  
Raman Spectroscopic ◽  
Uv Resonance Raman ◽  
Uv Resonance Raman Spectroscopy ◽  
Ion Laser ◽  
Chir Pine

Abstract The effect of laser irradiation (Ar+ ion laser, 244 nm) on photodegradation of lignin in silver birch and rubberwood as hardwoods and spruce and chir pine as softwoods has been investigated by UV resonance Raman spectroscopy (UVRRS). UVRR spectra showed degradation of aromatic structures accompanied by the formation of both ortho- and para-quinone structures as a result of photodegradation of wood surfaces. There was a rapid decrease in the intensities of all the lignin-associated bands accompanied by broadening of aromatic bands at 1602 cm-1 and in the region of 1500–1000 cm-1 due to formation of unsaturated structures arisen from lignin degradation. The rate of lignin degradation was observed by measuring the relative intensity of aromatic band at 1602 cm-1 during photodegradation. The rates of UV-degradation of hardwood and softwood surfaces were compared and it was found that hardwoods degrade at a faster rate than softwoods. The syringyl structures in hardwood lignin are more sensitive to photochemical degradation than guaiacyl structures. The rate of photodegradation increased with increasing intensity of the irradiated laser energy.

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