Enantioseparation by ligand-exchange using particle-loaded monoliths: capillary-LC versus capillary electrochromatography.
Particle-loaded monoliths containing a polymethacrylamide backbone were prepared by suspending a silica-based chiral phase in the mixture of the monomers followed by in-situ polymerization in the capillary. As chiral selector l-4-hydroxyproline chemically bonded to 3 microm silica particles was used following the separation principle of ligand-exchange. Electrolytes containing Cu(II) ions were used. Amino acid enantiomers were separated by capillary-LC and CEC, whereby the latter showed the better resolution properties. For the chiral separation of alpha-hydroxy acids the EOF was reversed by copolymerizing diallyldimethylammonium chloride instead of vinylsulfonic acid as charge providing agent. Short columns of 6 cm were found to be sufficient in the case of CEC for baseline separations of amino acids with alpha values up to 5.
Schmid
Martin G
MG
Institute of Pharmaceutical Sciences, Department of Pharmaceutical Chemistry, Karl-Franzens-University, Universitätsplatz 1, A-8010 Graz, Austria. martin.schmid@uni-graz.at
Koidl
Julia
J
Wank
Pamela
P
Kargl
Gabriele
G
Zöhrer
Helga
H
Gübitz
Gerald
G
D000178:Acrylamides; D053801:Capillary Electrochromatography / Q000379:methods*; D002853:Chromatography, Liquid / Q000379:methods*; D008024:Ligands; D008333:Mandelic Acids / Q000737:chemistry / Q000302:isolation & purification; D008855:Microscopy, Electron, Scanning; D010649:Phenylalanine / Q000737:chemistry / Q000302:isolation & purification; D011108:Polymers; D013237:Stereoisomerism; D014364:Tryptophan / Q000737:chemistry / Q000302:isolation & purification; D014443:Tyrosine / Q000737:chemistry / Q000302:isolation & purification
D000178:Acrylamides; D008024:Ligands; D008333:Mandelic Acids; D011108:Polymers; D014443:Tyrosine; D010649:Phenylalanine; D014364:Tryptophan; C045985:methacrylamide; C037938:mandelic acid