| Ionization behavior of aqueous short-chain carboxylic acids: a carbon-13 NMR study. | |
| | |
MedLine Citation:
|
PMID: 7119577 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
The 13C chemical shift of each carbon of aqueous acetic, propionic, and butyric acids has been measured as a function of pH or of added equivalents of base. A plot of chemical shifts for the carboxyl, alpha, and beta carbons as a function of pH is sigmoidal and yields pKa values that agree closely with values obtained by potentiometric titration. In contrast, a plot of chemical shift as a function of added equivalents of base is linear and has a sharp break at the equivalence point. Based on this result, we propose that the local (microscopic) ionization state of the carboxyl group can be determined directly by NMR without need for pH or pK determinations. In addition to titration curves, the effects of concentration, ionic strength, and temperature upon fatty acid chemical shifts are reported. For aqueous acids, changes in ionic strength and temperature have no effect on chemical shifts. However, changes in concentration do affect chemical shifts, probably as a result of changes in the relative degree of acid-acid and acid-water hydrogen bonding. Our results provide necessary background data for 13C NMR studies of higher fatty acids in lipid-lipid and lipid-protein systems. |
| | |
Authors:
|
D P Cistola; D M Small; J A Hamilton |
Related Documents
:
|
12168527 - Comparison of the electrochemical properties of some colon-specific prodrugs of mesalaz... 20238107 - Targeted lc-ms derivatization for aldehydes and carboxylic acids with a new derivatizat... 11925227 - Nucleophilic catalysis with 1,8-diazabicyclo[5.4.0]undec-7-ene (dbu) for the esterifica... 19571417 - Combining a solution-phase derived library with in-situ cellular bioassay: prompt scree... 4041477 - The presence of 5 alpha-sitostanol in the serum of a patient with phytosterolemia, and ... 17618427 - Tolfenamic acid is a potent cyp1a2 inhibitor in vitro but does not interact in vivo: co... |
Publication Detail:
|
Type: Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
|
Title: Journal of lipid research Volume: 23 ISSN: 0022-2275 ISO Abbreviation: J. Lipid Res. Publication Date: 1982 Jul |
Date Detail:
|
Created Date: 1982-12-02 Completed Date: 1982-12-02 Revised Date: 2007-11-14 |
Medline Journal Info:
|
Nlm Unique ID: 0376606 Medline TA: J Lipid Res Country: UNITED STATES |
Other Details:
|
Languages: eng Pagination: 795-9 Citation Subset: IM |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Acetic Acid Acetic Acids Butyric Acid Butyric Acids Carboxylic Acids* Magnetic Resonance Spectroscopy Propionic Acids |
| Grant Support | |
ID/Acronym/Agency:
|
HL07291/HL/NHLBI NIH HHS; HL26335/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
|
0/Acetic Acids; 0/Butyric Acids; 0/Carboxylic Acids; 0/Propionic Acids; 107-92-6/Butyric Acid; 64-19-7/Acetic Acid; 79-09-4/propionic acid |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Diet-induced and physiologically occurring hypercholesterolemias in the spontaneous hypothyroid Euro...
Next Document: Pattern formation in morphogenesis. Analytical treatment of the Gierer-Meinhardt model on a sphere.