title: Dual CD system in capillary electrophoresis for direct separation of the four stereoisomers of agonist and antagonist melatoninergic ligands.
abstract: In this study, baseline separation of the stereoisomers of six tetrahydronaphthalenic derivatives (agonists and antagonists for the melatonin (N-acetyl-5-methoxytryptamin) binding sites) was successfully achieved using CE and CDs as chiral selectors. The method for the simultaneous chiral separation of the four stereoisomers uses a capillary dynamically coated with polyethylene oxide and a dual CD system. Optimisation was performed first upon the constituents of the CD system, by varying neutral and anionic CD type, size and concentration, at first in mono-CD systems and subsequently in dual neutral/anionic CD systems. Once these characteristics of the dual CD system were established, operational parameters such as voltage and temperature were then optimised. Under the optimal conditions (i.e. 1.5% w/v of highly S-beta-CD and 10 mM of gamma-CD in 25 mM phosphate buffer (pH 2.5) as the BGE, separation voltage 20 kV and a temperature of 25 degrees C), complete resolution of the six molecules was accomplished. Preliminary results for repeatability and the migration order of the optimised method are described.
authors.affiliation: Laboratoire de Chimie Analytique, EA, Lille France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Lipka
authors.forename: Cécile
authors.initials: C
authors.lastname: Danel
authors.forename: Saïd
authors.initials: S
authors.lastname: Yous
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Bonte
authors.forename: Claude
authors.initials: C
authors.lastname: Vaccher
mesh_terms: D003505:Cyclodextrins / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000379:methods*; D008550:Melatonin / Q000819:agonists / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D013237:Stereoisomerism; D013696:Temperature; D013764:Tetrahydronaphthalenes / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D003505:Cyclodextrins; D013764:Tetrahydronaphthalenes; D011092:Polyethylene Glycols; D008550:Melatonin