An analytical method has been developed for assay of unsaturated disaccharides of chondroitin sulfates and of oligosaccharides (tetra- and hexasaccharides) of hyaluronan, using ion-association capillary zone electrophoresis. Samples were applied at the anode (the usual polarity), using a borate buffer modified by an ion-pairing reagent, tetrabutylammonium (TBA) phosphate, and the effect of the concentration of the ion-pairing reagent on various electrophoretic parameters (electroosmotic flow, electrophoretic mobility of products, capacity factors) was observed. Increasing concentrations of the reagent led to a decrease of zeta potential, probably due to specific adsorption of the quaternary ammonium ion onto the capillary wall. The authors propose a mechanism of separation, in which anionic borate complexes are formed and interact with TBA ion inside the capillary tube. The capillary electrophoretic system described is potentially a powerful method for specific measurement of the concentrations in joint tissues of chondroitin 4-sulfate, chondroitin 6-sulfate, and hyaluronan, whose relative abundances may vary in various diseases or after local treatments with, for example, antiinflammatory drugs, chondroprotective agents, or orthopedic implants.
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http://dx.doi.org/10.1021/ac9800558 | DOI Listing |
Anal Sci
May 2015
Department of Life System, Institute of Technology and Science, The University of Tokushima.
The ion-association equilibrium of the dipicrylaminate ion (DPA(-)) was investigated in an aqueous solution with alkali metal ions and with its 18-crown-6 ether complexes as pairing cations by capillary zone electrophoresis (CZE). Although DPA(-) is precipitable with the pairing cations of K(+) and Cs(+) in a homogenous aqueous solution, a low concentration of DPA(-) below its solubility suppressed the formation of the precipitates, and DPA(-) was detected as a usual CZE signal. Changes in the electrophoretic mobility of DPA(-) was analyzed for its ion-association equilibrium.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
June 2014
Howard P. Isermann Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180
There is overwhelming evidence that ions are present near the vapor-liquid interface of aqueous salt solutions. Charged groups can also be driven to interfaces by attaching them to hydrophobic moieties. Despite their importance in many self-assembly phenomena, how ion-ion interactions are affected by interfaces is not understood.
View Article and Find Full Text PDFAnalyst
July 2011
Graduate School of Science and Engineering, Saitama University, Sakura-ku, Japan.
Novel fluorescent probes have been developed for the ultratrace detection of heavy metal ions by capillary electrophoresis using laser-induced fluorescence detection. Based on a molecular design, the probes are composed of an octadentate chelating moiety, a macrocyclic DOTA (tetraazacyclododecanetetraacetic acid) and an acyclic DTPA (diethylenetriaminepentaacetic acid) frame, a spacer and a fluorophore (fluorescein). These were chosen on the basis of their ability to form kinetically inert and highly emissive complexes, and to prevent a quenching effect even with heavy and paramagnetic metal ions.
View Article and Find Full Text PDFAnal Sci
June 2011
Graduate School of Environmental Studies, Tohoku University, 20 Aoba, Aramaki, Aoba, Sendai 980–8579, Japan.
The effect of urea as an electrophoretic buffer solution modifier on the ion-association (IA) capillary electrophoresis (CE) separation of four anionic metal complexes of Al(III), Co(III), Cr(III), and Fe(III) with 2,2'-dihydroxyazobenezene-5,5'-disulfonate (DHABS) using a hydrophobic ion-association agent, tetrapentylammonium bromide, was studied. The mutual separation of the four anionic metal-DHABS complexes was not achieved without the addition of urea in the electrophoretic buffer solution. However, the addition of 1.
View Article and Find Full Text PDFTalanta
April 2007
Department of Chemistry, Lanzhou University, Lanzhou, China; State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, China.
A capillary zone electrophoresis method using only 1-alkyl-3-methylimidazolium-based ionic liquids as background electrolyte for the simultaneous determination of five anthraquinone derivatives including aloe-emodin, emodin, chrysophanol, physcion and rhein in Rhubarb species was described. Ion association constants, K(ass), between anthraquinone anions and imidazolium cations were determined by analyzing the electrophoretic mobility change of anthraquinone anions using a non-linear least-squares method and factors contributing to ion associability were systematically clarified. For method optimization, several parameters such as ionic liquids concentration, background electrolyte pH and applied voltage, on the separation were evaluated and the optimum conditions were obtained as follows: 90mM 1-butyl-3-methylimidazolium tetrafluoroborate (pH 11.
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