title: Chiral ion-exchange capillary electrochromatography of arylglycine amides with dextran sulfate as a pseudostationary phase.
abstract: A low-cost tunable chiral ion-exchange capillary electrochromatographic method has been developed for the separation of arylglycine amide racemic mixtures with dextran sulfate (DS) as an anionic and chiral pseudostationary phase and Tris-tartrate as a buffer system. The concentrations of DS and Tris had opposite influences on retention and resolution and could serve as ideal factors to finely tune the running speed and chiral resolution. Tartrate and pH largely impact the separation but pH should be confined within 3.0-5.5, only suitable for coarse tuning, while tartrate was preserved as the key buffering reagent, normally maintained at 40 mmol/L. With a working system composed of 0.1-1.0% DS, 20-60 mmol/L Tris, and 40 mmol/L tartrate at pH 3.50-4.50, the enantioresolution of arylglycine amides was shown to be dependent on their chemical structure: The chiral resolution increased when the hydrogen at the alpha-amino group or at the p-position of phenyl ring was replaced by other larger group(s) but the resolution decreased when the group at the o- or m-site on the phenyl ring was enlarged. Further, the electronegative substitute of -Cl had larger resolution increment than methyl or methoxy at the position p- of phenyl ring but much lower increment at position m-. It is possible to well explain the resolution variation phenomenon by considering the group resistance and the variation of hydrogen-bonds formed inside the amino amides and between the solutes and DS. The amido group was shown irreplaceable to have chiral resolution with DS alone as an ionic and chiral pseudostationary phase.
authors.affiliation: Laboratory of Analytical Chemistry for Life Science, Department of Chemical Biology, Institute of Chemistry, Chinese Academy of Science, Beijing, P.R. China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Laboratory of Analytical Chemistry for Life Science, Department of Chemical Biology, Institute of Chemistry, Chinese Academy of Science, Beijing, P.R. China.
authors.forename: Xiaoning
authors.initials: X
authors.lastname: Lu
authors.affiliation: Laboratory of Analytical Chemistry for Life Science, Department of Chemical Biology, Institute of Chemistry, Chinese Academy of Science, Beijing, P.R. China.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Han
authors.affiliation: Laboratory of Analytical Chemistry for Life Science, Department of Chemical Biology, Institute of Chemistry, Chinese Academy of Science, Beijing, P.R. China.
authors.forename: Li
authors.initials: L
authors.lastname: Qi
authors.affiliation: Laboratory of Analytical Chemistry for Life Science, Department of Chemical Biology, Institute of Chemistry, Chinese Academy of Science, Beijing, P.R. China.
authors.forename: Mei Xiang
authors.initials: MX
authors.lastname: Wang
authors.affiliation: Laboratory of Analytical Chemistry for Life Science, Department of Chemical Biology, Institute of Chemistry, Chinese Academy of Science, Beijing, P.R. China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Yu
authors.affiliation: Laboratory of Analytical Chemistry for Life Science, Department of Chemical Biology, Institute of Chemistry, Chinese Academy of Science, Beijing, P.R. China.
authors.forename: Gengliang
authors.initials: G
authors.lastname: Yang
authors.affiliation: Laboratory of Analytical Chemistry for Life Science, Department of Chemical Biology, Institute of Chemistry, Chinese Academy of Science, Beijing, P.R. China.
authors.forename: Lanqun
authors.initials: L
authors.lastname: Mao
authors.affiliation: Laboratory of Analytical Chemistry for Life Science, Department of Chemical Biology, Institute of Chemistry, Chinese Academy of Science, Beijing, P.R. China.
authors.forename: Huiming
authors.initials: H
authors.lastname: Ma
mesh_terms: D002021:Buffers; D002852:Chromatography, Ion Exchange / Q000379:methods*; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D016264:Dextran Sulfate; D005998:Glycine / Q000031:analogs & derivatives* / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D012492:Salts; D013237:Stereoisomerism; D014325:Tromethamine
chemical_list: D002021:Buffers; D012492:Salts; D014325:Tromethamine; C018556:glycine amide; D016264:Dextran Sulfate; D005998:Glycine
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