pH and pKDeterminations by High-Resolution Solid-State13C NMR:  Acid−Base and Tautomeric Equilibria of Lyophilizedl-Histidine

2002 ◽  
Vol 124 (9) ◽  
pp. 2025-2034 ◽  
Author(s):  
Bernard Henry ◽  
Piotr Tekely ◽  
Jean-Jacques Delpuech
Keyword(s):  
High Resolution ◽  
Acid Base ◽  
Tautomeric Equilibria

Demonstration of High-Resolution Capability of Chemical Force Titration via Study of Acid/Base Properties of a Patterned Self-Assembled Monolayer

Langmuir ◽  
2000 ◽  
Vol 16 (2) ◽  
pp. 517-521 ◽  
Author(s):  
Hui-Xin He ◽  
Wei Huang ◽  
Hua Zhang ◽  
Qi Guang Li ◽  
Sam Fong Yau Li ◽  
...  
Keyword(s):  
High Resolution ◽  
Acid Base ◽  
Self Assembled Monolayer ◽  
Resolution Capability ◽  
Self Assembled ◽  
Chemical Force ◽  
Base Properties

Acid-Base Relationships and Tautomeric Equilibria in m-Aminobenzoic Acid, 3-Amino-1-naphthoic Acid, and 4-Amino-2-naphthoic Acid

1961 ◽  
Vol 14 (2) ◽  
pp. 237 ◽  
Author(s):  
A Bryson ◽  
RW Matthews
Keyword(s):  
Aqueous Solution ◽  
Methyl Esters ◽  
Ionization Constants ◽  
Aminobenzoic Acid ◽  
Naphthalene Ring ◽  
Acid Base ◽  
Tautomeric Equilibria ◽  
Naphthoic Acid

The first and second ionization constants have been determined in aqueous solution of m-aminobenzoic acid, 3-amino-1-naphthoic acid, and 4-amino-2-naphthoic acid. From published values of the ionization constants for the methyl esters, the ionization constants have been evaluated for the four equilibria involved in each case and estimates have been made of the effects of the substituents NH3+ and NH2 on the ionization of the COOH, and of the substituents COOH and COO- on the ionization of the NH3+ group. These values and the tautomeric constants are interpreted in terms of structure and are discussed in relation to previous studies on substitution in the naphthalene ring.

High-Resolution Peat Core Chronology Covering the Last 12 KYR Applying an Improved Peat Bog Sampling

Radiocarbon ◽  
2018 ◽  
Vol 60 (5) ◽  
pp. 1367-1378 ◽  
Author(s):  
Katalin Hubay ◽  
Mihály Braun ◽  
Sándor Harangi ◽  
László Palcsu ◽  
Marianna Túri ◽  
...  
Keyword(s):  
High Resolution ◽  
Accumulation Rate ◽  
Peat Bog ◽  
Acid Base ◽  
Peat Accumulation ◽  
Peat Core ◽  
Ams Dating ◽  
Different Depths ◽  
Peat Profile ◽  
Bleaching Step

ABSTRACTThis work focuses on building a high-resolution age-depth model for quantitative palaeoclimate study from the Mohos peat bog, East Carpathian mountains. The investigated core presents a continuous peat profile for the last 12 kyr. The chronology was based on 36 accelerator mass spectrometry radiocarbon (AMS 14C) analyses of the separated Sphagnum samples from different depths of the profile. Dry Sphagnum samples for AMS dating were prepared using the classic acid-base-acid (ABA) method followed with an oxidative bleaching step to get clean cellulose. Sphagnum cellulose samples were measured by AMS using the EnvironMICADAS at the ICER (Debrecen, Hungary). A high-resolution chronology was obtained with the use of Bayesian age-depth modeling. Peat accumulation rate has been calculated and the sections with variable accumulation rate values were observed along the profile.

ChemInform Abstract: 13C NMR Study of Acid-Base Tautomeric Equilibria

ChemInform ◽  
1987 ◽  
Vol 18 (32) ◽  
Author(s):  
L. M. SCHWARTZ ◽  
R. I. GELB ◽  
J. MUMFORD-ZISK ◽  
D. A. LAUFER
Keyword(s):  
13C Nmr ◽  
Acid Base ◽  
Tautomeric Equilibria ◽  
Nmr Study
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