scholarly journals Comparative analysis of the structure of coals of different stages of metamorphism according to 13C NMR data

2020 ◽  
Vol 63 (8) ◽  
pp. 53-57
Author(s):  
Sergey Yu. Lyrshchikov ◽  
◽  
Larisa V. Sotnikova ◽  
Keyword(s):  
13C Nmr ◽  
Quantitative Data ◽  
13C Nmr Spectroscopy ◽  
Raw Material ◽  
Magic Angle ◽  
Wide Range ◽  
Degree Of Aromaticity ◽  
Angle Rotation ◽  
Cpmas 13C Nmr ◽  
Spectrum Model

In this paper, the method of cross-polarization with magic angle rotation and decoupling from protons (CPMAS) 13C NMR spectroscopy obtained quantitative data on the distribution of carbon over structural fragments and calculated the degree of aromaticity (fa) of some coal samples from various Siberian deposits of a wide range of metamorphism. All the coals used in the work were characterized by standard methods (proxymate and ultimate analysis). The optimal parameters of the pulse program for recording the spectra of coals have been determined. To obtain quantitative data, the spectra were simulated. The spectrum model included from 9 to 13 components, depending on the stage of coal metamorphism. The dependences of the degree of aromaticity and the sum of oxygen-containing functional groups on the stage of coal metamorphism were constructed. The results obtained show that the structure of coals regularly changes depending on the stage of their metamorphism. The revealed relationships of the structure and properties of coals, together with the parameters of their reactivity, can ensure the safe behavior of coals in the processes of mining and processing, as well as in determining possible ways of using the studied coal samples as a valuable chemical raw material.

Intracellular pH determination by 13C-NMR spectroscopy

1993 ◽  
Vol 264 (3) ◽  
pp. C755-C760 ◽  
Author(s):  
V. P. Chacko ◽  
R. G. Weiss
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Shift ◽  
Intracellular Ph ◽  
13C Nmr ◽  
Nonlinear Least Squares ◽  
13C Nmr Spectroscopy ◽  
31P Nmr Spectroscopy ◽  
Rat Hearts ◽  
13C Nuclear Magnetic Resonance ◽  
Wide Range

A noninvasive method for the determination of pH by the 13C-nuclear magnetic resonance (NMR) chemical shift of the C-3 carbon of sn-glycerol 3-phosphate is described. Nonlinear least-squares analysis of the chemical shift variation of the C-3 resonance of sn-glycerol 3-phosphate with pH at 37 degrees C in solutions and in perchloric acid extracts of tissue yielded a pKa of 6.2, making it a very sensitive indicator of pH in the approximate range of 5-7. Intracellular pH determined by the present 13C-NMR method correlated well with simultaneous measurements of pH by 31P-NMR spectroscopy over a wide range during normal perfusion and ischemic conditions in intact rat hearts. These findings indicate that this approach is particularly suited for quantification of intracellular pH over the physiological range in intact tissues and that observed in ischemic myocardium.

ChemInform Abstract: High-Field Magic-Angle-Spinning 13C NMR Spectroscopy of Co4(CO)12.

ChemInform ◽  
1989 ◽  
Vol 20 (26) ◽  
Author(s):  
S. AIME ◽  
M. BOTTA ◽  
R. GOBETTO ◽  
B. E. HANSON
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
High Field ◽  
13C Nmr Spectroscopy ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Angle Spinning

scholarly journals Adsorption of dissolved organic matter on clay minerals as assessed by infra-red, CPMAS 13C NMR spectroscopy and low field T1 NMR relaxometry

2011 ◽  
Vol 42 (8) ◽  
pp. 972-977 ◽  
Author(s):  
Pellegrino Conte ◽  
Cristina Abbate ◽  
Andrea Baglieri ◽  
Michéle Nègre ◽  
Claudio De Pasquale ◽  
...  
Keyword(s):  
Organic Matter ◽  
Nmr Spectroscopy ◽  
Dissolved Organic Matter ◽  
Clay Minerals ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
Low Field ◽  
Nmr Relaxometry ◽  
Infra Red ◽  
Cpmas 13C Nmr
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