Enantiomer separation of denopamine by capillary electrophoresis with charged and uncharged cyclodextrins

Abstract

Direct separation of enantiomers of denopamine was investigated by capillary electrophoresis employing charged and uncharged cyclodextrin (CD) derivatives. Uncharged beta-type CDs, having hydrophobic groups, were essential for the enantioseparation of denopamine; of these, especially dimethyl-beta-CD was effective. Among charged CDs, gamma-type as well as beta-type CDs were found effective for the enantioseparation of denopamine. Reversal of migration order of R-form (active) and S-form enantiomers was investigated by using two types of coated capillaries: (i) an amine capillary with an inner wall coated with dimethylamino groups, and (ii) a polyacrylamide-coated capillary. Manipulation of migration order could be easily performed by selecting suitable capillaries, buffer pH, and CDs.

Enantiomer migration order in chiral capillary electrophoresis

“…The most interesting feature of this technique is that the migration order of enantiomers can be reverted without affecting the enantioselective interactions in the separation system and just applying an additional nonenantioselective migration force. Such forces are many and of different nature as it has been summarized in the earlier review article [1] and employed in many research articles published in the recent years [32][33][34][35][36][37][38][39][40][41][42][43][44][45]. Some of these examples are realized by reverting the polarity of the high-voltage supply.…”

Chiral separation by chromatographic and electromigration techniques. A Review

“…Carboxyl functional CDs such as carboxymethyl-b-CD (CM-b-CD) [355] carboxyethyl-b-CD (CE-b-CD) [355] and succinyl-b-CD [355,356] found application to a broad spectrum of neutral and basic compounds [13,15,16]. Phosphated CDs [357,358] are another group of negatively charged CDs successfully applied to the separation of some drug enantiomers.…”

Chiral Recognition and Enantioseparation Mechanisms in Capillary Electrokinetic Chromatography

“…The most interesting feature is the fact that the migration order of enantiomers can be reversed without affecting enantioselective interactions in the separation system and by just applying an additional nonenantioselective migration force. Such forces are many and of different nature as it has been summarized in the earlier review article [17] and employed in many research articles published in the recent years [19,47,52,[142][143][144][145][146][147][148][149]. Some of these reversals of EMO were achieved by reversing the polarity of the high voltage supply.…”