title: Separation of amino-acid enantiomers using micellar-enhanced ultrafiltration.
abstract: Micellar-enhanced ultrafiltration (MEUF) is investigated as a large-scale technique for separating amino acid enantiomers. Specifically, L-5-cholesterol glutamate, a chiral ligand-exchange cosurfactant, is used together with a nonionic surfactant to form mixed micelles that preferentially bind D-phenylalanine over L-phenylalanine in the presence of copper(II). Operational selectivities as high as 4.2 are obtained. Potentiometric titrations using a water-soluble model compound similar to the chiral cosurfactant indicate that the ternary copper complex with phenylalanine has a stereoselectivity for the D enantiomer which is significantly smaller than that observed in the MEUF system. Thus, the selectivity of the chiral legend's local solvent and structural environment.
authors.affiliation: Wageningen Agricultural University, Food and Bioprocess Engineering group, Department of Food Science, Biotechnion, PO Box 8129, 6700 EV Wageningen, The Netherlands.
authors.forename: A L
authors.initials: AL
authors.lastname: Creagh
authors.forename: B B
authors.initials: BB
authors.lastname: Hasenack
authors.forename: A
authors.initials: A
authors.lastname: Van der Padt
authors.forename: E J
authors.initials: EJ
authors.lastname: Sudhölter
authors.forename: K
authors.initials: K
authors.lastname: Van't Riet