scholarly journals Distinguishing Benign from Malignant Pancreatic and Periampullary Lesions Using Combined Use of 1H-NMR Spectroscopy and Gas Chromatography–Mass Spectrometry

Metabolites ◽  
2017 ◽  
Vol 7 (1) ◽  
pp. 3 ◽  
Author(s):  
Yarrow McConnell ◽  
Farshad Farshidfar ◽  
Aalim Weljie ◽  
Karen Kopciuk ◽  
Elijah Dixon ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Gas Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry ◽  
Combined Use

Comparison of hydrogenolysis with thioacidolysis for lignin structural analysis

Holzforschung ◽  
2014 ◽  
Vol 68 (2) ◽  
pp. 151-155 ◽  
Author(s):  
Daniel J. van de Pas ◽  
Bernadette Nanayakkara ◽  
Ian D. Suckling ◽  
Kirk M. Torr
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Gas Chromatography ◽  
Nmr Spectroscopy ◽  
Structural Analysis ◽  
Magnetic Resonance ◽  
Gas Chromatography Mass Spectrometry ◽  
Aryl Ether ◽  
Chromatography Mass Spectrometry

Abstract Mild hydrogenolysis has been compared with thioacidolysis as a method for degrading lignins in situ and in isolated form before analysis by gas chromatography/mass spectrometry and quantitative 31P nuclear magnetic resonance (NMR) spectroscopy. Both degradation methods gave similar levels of β-aryl ether-linked phenylpropane units that were released as monomers. Degradation by hydrogenolysis generally gave lower levels of total phenylpropane units when analyzed by 31P NMR, especially in the case of lignins with high levels of condensed units. Overall, these results indicate that mild hydrogenolysis could offer an alternative to thioacidolysis for probing lignin structure.

EFFECT OF STEREOCHEMISTRY IN ANIONIC POLYMERIZATION MODIFIERS

2017 ◽  
Vol 90 (2) ◽  
pp. 325-336
Author(s):  
Terrence E. Hogan ◽  
Waruna Kiridena ◽  
Laura Kocsis
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
1H Nmr ◽  
Column Chromatography ◽  
Anionic Polymerization ◽  
Gas Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry

ABSTRACT The influence of stereochemistry of polar modifiers on the microstructure of polybutadiene and poly(styrene-co-butadiene) was evaluated for 2,2′-ditetrahydrofurylpropane (DTHFP). The meso and d,l diastereomers were isolated from commercial 50/50 mixtures through column chromatography and characterized by 1H-NMR and gas chromatography/mass spectrometry. The meso-DTHFP was found to be more active than d,l-DTHFP in incorporation of vinyl during anionic polymerization. To form a polymer with approximately 55% vinyl, twice the amount of d,l-DTHFP was required compared with using pure meso-DTHFP. The mechanism for this effect will be discussed.

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