title: Separating stereoisomers of di-, tri-, and tetrapeptides using capillary electrophoresis with contactless conductivity detection.
abstract: The separation and detection of small oligopeptides in CE with contactless conductivity detection were demonstrated. A strongly acidic separation buffer (0.5 M acetic acid) was employed in order to render the species cationic. Separation of the stereoisomers was achieved in typically 10-15 min by using either dimethyl-beta-CD (DM-beta-CD), (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid (18C(6)H(4)), a combination of the two substances, or of histidine, as buffer additives. Calibration curves were determined for isomers of Gly-Asp and H-Pro-Asp-NH(2), in the range of 0.05-0.5 mM and 0.1-1 mM, respectively, and were found to be linear. LODs were determined to be in the order of 1.0 microM. The determination of isomeric impurities down to about 1% was found possible. Species showing good separation could also be successfully determined on an electrophoretic lab-on-chip device, with analysis times of a few minutes.
authors.affiliation: Department of Chemistry, University of Basel, Spitalstrasse 51, Basel, Switzerland.
authors.forename: Xiao Yang
authors.initials: XY
authors.lastname: Gong
authors.forename: Dominik
authors.initials: D
authors.lastname: Dobrunz
authors.forename: Michael
authors.initials: M
authors.lastname: Kümin
authors.forename: Markus
authors.initials: M
authors.lastname: Wiesner
authors.forename: Jefferson D
authors.initials: JD
authors.lastname: Revell
authors.forename: Helma
authors.initials: H
authors.lastname: Wennemers
authors.forename: Peter C
authors.initials: PC
authors.lastname: Hauser
mesh_terms: D004553:Electric Conductivity; D019075:Electrophoresis, Capillary / Q000379:methods*; D015394:Molecular Structure; D009842:Oligopeptides / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013237:Stereoisomerism; D013997:Time Factors
chemical_list: D009842:Oligopeptides