TITLE

Raman spectroscopic study of the conformational order of octadecylsilane stationary phases: effects of electrolyte and pH

AUTHOR(S)
Orendorff, Christopher J.; Pemberton, Jeanne E.
PUB. DATE
June 2005
SOURCE
Analytical & Bioanalytical Chemistry;Jun2005, Vol. 382 Issue 3, p691
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
This study investigates effects of the electrolyte, of acidic and basic compounds, and of pH on the rotational and conformational order of octadecylsilane stationary phases with surface coverages of 3.09 and 6.45 µmol/m2. Both phases exhibit an increase in alkyl chain rotational and conformational order in 5-200 mM aqueous electrolyte solutions relative to water. These stationary phases are effectively “salted-out” of aqueous electrolyte solutions, thereby causing alkyl chain intermolecular interactions to increase with a concomitant increase in alkyl chain order. Although the presence of acidic and basic compounds generally has no effect on the conformational order of either stationary phase as a function of pH, the higher coverage stationary phase does exhibit pH-dependent changes in aqueous solutions of benzoic acid. At pH values below the pKa of benzoic acid, the conformational order of this stationary phase is unchanged relative to that observed in the same pH solution in the absence of benzoic acid. In light of independent evidence that such monosubstituted aromatics interact with the octadecylsilane stationary phase under these conditions, the absence of a measurable effect on alkyl chain order for these conditions is attributed to benzoic acid self-association at the stationary phase-mobile phase interface. In contrast, at pH values above the pKa of benzoic acid, slight disordering of the alkyl chains is observed and is attributed to repulsive interactions between retained benzoate anions.
ACCESSION #
17211503

 

Related Articles

  • Enhanced negative ion formation in ultraviolet-laser irradiated silane: Implications for plasma.... Pinnaduwage, Lal A.; Martin, Madhavi Z. // Applied Physics Letters;11/14/1994, Vol. 65 Issue 20, p2571 

    Observes the enhancement of negative ion formation in ultraviolet-laser irradiated silane. Role of silane photofragments in electron attachment enhancement; Production of highly excited electronic states in silane plasmas; Importance of electron attachment process for negative ion formation;...

  • 2-[(1-Benzamido-2-methoxy-2-oxoethyl)amino]benzoic Acid. El Houssine, Mabrouk; Abdelrhani, Elachqar; Abdelilah, El Hallaoui; Anouar, Alami // Molbank;Mar2013, Vol. 13 Issue 1, Special section p1 

    The carboxylic α, α-diaminoester 2-[(1-benzamido-2-methoxy-2-oxoethyl) amino]benzoic acid is obtained by N-alkylation of methyl α-azido glycinate N-benzoylated with 2-aminobenzoic acid.

  • Synthesis of 2,4,6-trisubstituted 5-(2-alkylsulfanylethyl)-pyrimidines and some their transformations. Arutyunyan, A. // Russian Journal of Organic Chemistry;Dec2013, Vol. 49 Issue 12, p1753 

    New 2,4,6-trisubstituted 5-(2-alkylsulfanylethyl)pyrimidines were synthesized by condensation of ethyl 2-(2-alkylsulfanylethyl)-3-oxobutanoates with various amidines and thiourea. Fusion of substituted 2,6-dimethylpyrimidin-4(3 H)-ones with aromatic aldehydes gave the corresponding...

  • Complex formation of uranium(VI) with 4-hydroxy-3-methoxybenzoic acid and related compounds. Vulpius, D.; Geipel, G.; Baraniak, L.; Rossberg, A.; Bernhard, G. // Journal of Radioanalytical & Nuclear Chemistry;Dec2006, Vol. 270 Issue 3, p661 

    The complex formation of uranium(VI) with 4-hydroxy-3-methoxybenzoic acid as well as with benzoic acid and 4-hydroxybenzoic acid was studied. In aqueous solution weak carboxylic 1 : 1 complexes, are formed in which the carboxyl group is bidentately coordinated to the metal atom. The logarithmic...

  • Reduction of ionic strength activates single volume-regulated anion channels (VRAC) in endothelial cells. Sabirov, R. Z.; Prenen, J.; Tomita, T.; Droogmans, G.; Nilius, B. // Pflugers Archiv European Journal of Physiology;Jan2000, Vol. 439 Issue 3, p315 

    We have previously shown that a reduction of intracellular ionic strength is involved in the activation of volume-regulated anion channels (VRAC). Here we show in a single-channel study that VRAC can be activated in a cell-attached patch when the cell interior is dialyzed with a solution of...

  • New polymer gel electrolytes containing chloro substituted aromatic carboxylic acids. Singh, H. P.; Sekhon, S. S. // Journal of Materials Science Letters;Aug2003, Vol. 22 Issue 15, p1053 

    Investigates the effect of the dissociation constant of different weak acids used and the polymer on the conductivity behavior of gel electrolytes. Effect of the electron withdrawing power of the substituted group; Conductivity of electrolytes containing different chlorobenzoic acids; Suggestion...

  • Anodic Corrosion of Copper in Presence of Organic Compounds. Elkashlan, Howaida M.; Ahmed, A. M. // International Journal of Electrochemical Science;Jul2012, Vol. 7 Issue 7, p5779 

    The electropolishing setting for the inhibiting the rate of anodic corrosion of copper plates in phosphoric acid were achieved using potentiodynamic studies including different factors such , plate height, conc of additives ,type of additives and temperature. The results reveal that benzoic acid...

  • Photoelectrocatalytic Performance of Benzoic Acid on TiO2 Nanotube Array Electrodes. Hongchong Chen; Jinhua Li; Quanpeng Chen; Di Li; Baoxue Zhou // International Journal of Photoenergy;2013, p1 

    The photoelectrocatalytic performance of benzoic acid on TiO2 nanotube array electrodes was investigated. A thin-cell was used to discuss the effect of the bias voltage, illumination intensity, and electrolyte concentration on the photoelectrocatalytic degradation efficiency of benzoic acid. The...

  • Preparative synthesis of 3- and 4-(3-alkoxy-4-acyloxyphenylmethylamino)benzoic acids. Dikusar, E. A.; Potkin, V. I.; Kozlov, N. G.; Kadutskii, A. P. // Russian Journal of Organic Chemistry;Jun2009, Vol. 45 Issue 6, p853 

    Reduction of 3- and 4-[(3-alkoxy-4-acyloxyphenyl)methylideneamino]benzoic acids ( E isomers) with sodium triacetoxyhydridoborate in benzene gave the corresponding 3- and 4-(3-alkxy-4-acyloxyphenylmethyl) benzoic acids in preparative yields.

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics