31P NMR titration and spectrophotometric titration of thiamine pyrophosphate

1984 ◽  
Vol 317 (6) ◽  
pp. 697-698 ◽  
Author(s):  
H. Lachmann ◽  
A. Freund ◽  
K. D. Schnackerz
Keyword(s):  
31P Nmr ◽  
Spectrophotometric Titration ◽  
Thiamine Pyrophosphate ◽  
Nmr Titration

Mononucleotides 31P NMR relaxation measurement

1983 ◽  
Vol 80 ◽  
pp. 831-832 ◽  
Author(s):  
A.M. Avedikian ◽  
D. Besserre ◽  
M. Delepierre
Keyword(s):  
31P Nmr ◽  
Nmr Relaxation ◽  
Relaxation Measurement

Experimental and Theoretical Investigations of Complex Formation of Substituted Phenylazo-Derivatives of Methylphloroglucinol

2016 ◽  
Vol 12 (8) ◽  
pp. 295-300
Author(s):  
Olga Kovalchukova ◽  
Amangdam A.T. ◽  
Strashnova S.B. ◽  
Strashnov P.V. ◽  
Romashkina E.P. ◽  
...  
Keyword(s):  
Complex Formation ◽  
Organic Ligand ◽  
Spectrophotometric Titration ◽  
Organic Ligands ◽  
Oh Groups ◽  
Tautomeric Forms ◽  
Theoretical Investigations ◽  
Derivatives Of ◽  
Theoretical Results ◽  
Titration Technique

Using spectrophotometric titration technique, the processes of complex formation of some phenylazo-derivatives of methylphloroglucinol (MPG) containing hydroxo-, nitro- and nitroso-substituents were studied. The spectral criteria of neutral and ionized forms of the organic ligands in their different tautomeric forms were determined.It was detected that the complex formation is accompanied by formation of one or two chelate cycles which involve azo- or nitroso-fragments and neighboring OH-groups of the organic ligands. Different types of coordination lead to different changes in the electronic absorption spectra.The DFT-B3LYP modeling of a Ni(II) complex of α-hydroxyphenylazo MPG established the most probable coordination mode of the organic ligand: tridentate chelating dianion, distorted square coordination of Ni-cations including one water molecule.  The theoretical results are in a good accordance with the experimental data.

Quantitative Determination of Krill Oil Composition by ATR-FTIR, NIR, and 31P NMR Spectroscopy

2020 ◽  
Author(s):  
Ashraf Ismail ◽  
Sanaz Molaye Moghaddam ◽  
Jean-Pierre MetabanzoulouSarya Aziz ◽  
Jacqueline Sedman ◽  
Mazen Bahadi
Keyword(s):  
Nmr Spectroscopy ◽  
Quantitative Determination ◽  
31P Nmr ◽  
31P Nmr Spectroscopy ◽  
Krill Oil ◽  
Oil Composition

Human Orosomucoid: Dissociation of Tyrosines in the Systems Water-Low Aliphatic Alcohol

1997 ◽  
Vol 62 (10) ◽  
pp. 1533-1543
Author(s):  
Vladimír Karpenko ◽  
Jana Horálková ◽  
Milan Kodíček
Keyword(s):  
Human Serum ◽  
Systems Analysis ◽  
Titration Curve ◽  
Relative Permittivity ◽  
Structural Changes ◽  
Aliphatic Alcohol ◽  
Mixed Media ◽  
Spectrophotometric Titration ◽  
Electrostatic Effects

The influence of methanol, ethanol, propan-1-ol, and propan-2-ol on the dissociation of tyrosines of human serum orosomucoid (acid α1-glycoprotein) was studied. The content of alcohols was chosen so that their solutions had the same value of the relative permittivity. Then, the contribution of electrostatic effects was equal in all cases and the observed differences between aqueous and alcoholic solutions reflected other, nonelectrostatic effects in the studied systems. Analysis of the spectrophotometric titration curve revealed three kinds of tyrosine groups (n1, n2, n3), but only the values pK1 and pK2 could be calculated. The observed differences of pK values in aqueous and mixed media are discussed and compared with the structural changes of the orosomucoid molecule.

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