title: Photo-response assisted enantiomer separations on an azobenzene-modified gamma-cyclodextrin stationary phase in micro-HPLC.
abstract: The photo-responses of the retention and enantioseparation of several optical isomers were evaluated using an azobenzene-modified gamma-cyclodextrin stationary phase (Az gamma-CDSP) in micro-HPLC. UV light irradiation induced a decrease in the retention and the chiral selectivity for N-(3,5-dinitrobenzoyl)-1-phenylethylamine (DNBPEA) and N-(3,5-dinitrobenzoyl)-1-(1-naphtylethyl)amine (DNBNEA), while an increase was induced for dansylphenylalanine (DnsPhe) using a mixture of methanol and aqueous phosphate buffer as the mobile phase. No changes in the retention and the enantiomer separation of benzoin were observed with UV light irradiation. The retention behaviors were recovered by visible-light irradiation. It was speculated that the main factor of the change in the retention behavior was a change in the pi-pi interaction due to the azobenzene moiety of the stationary phase with photo-irradiation. Comparing the retention behavior before and after UV light irradiation, a suitable condition for obtaining a better resolution and enantiomer separation would be chosen using Az gamma-CDSP.
authors.affiliation: Division of Applied Chemistry, Graduate School of Engineering, Tokyo Metropolitan University, Hachioji, Japan. nakagama-tatsuro@c.metro-u.ac.jp
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Nakagama
authors.forename: Atsutoshi
authors.initials: A
authors.lastname: Yamaguchi
authors.forename: Kazuya
authors.initials: K
authors.lastname: Hirasawa
authors.forename: Koji
authors.initials: K
authors.lastname: Yoshida
authors.forename: Katsumi
authors.initials: K
authors.lastname: Uchiyama
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Hobo
mesh_terms: D001391:Azo Compounds; D001555:Benzene Derivatives; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003505:Cyclodextrins / Q000737:chemistry* / Q000302:isolation & purification; D007202:Indicators and Reagents; D008832:Microchemistry / Q000379:methods; D013237:Stereoisomerism
chemical_list: D001391:Azo Compounds; D001555:Benzene Derivatives; D003505:Cyclodextrins; D007202:Indicators and Reagents