Photo-responsive retention behavior of azobenzene-modified cyclodextrin stationary phase in micro-HPLC.
An azobenzene-modified gamma-cyclodextrin stationary phase (Az gamma-CDSP) was prepared and its photo- and temperature-responses for the retention of perylene and pentacene were investigated using a mixture of methanol and water as the mobile phase in micro-HPLC. The retention of perylene slightly increased, whereas that of pentacene significantly decreased by UV light irradiation to Az gamma-CDSP. These retentions recovered upon irradiation with visible light. Both retentions decreased upon an increase in the column temperature. It was presumed that the trans-azobenzene moiety acts as a preventive cap for perylene and a spacing for pentacene in filling the CD cavity. An azobenzene-modified stationary phase changed its retention behavior with the column temperature and the light irradiation. An improvement in the micro-HPLC system and the optimization of the molecular structure of the photo-responsive stationary phase would provide selective retention control by the irradiation of light in micro-separation systems.
Nakagama
T
T
Division of Applied Chemistry, Graduate School of Engineering, Tokyo Metropolitan University, Hachioji, Japan. nakagama-tatsuro@c.metro-u.ac.jp
Hirasawa
K
K
Uchiyama
K
K
Hobo
T
T
D001391:Azo Compounds / Q000737:chemistry* / Q000528:radiation effects; D002851:Chromatography, High Pressure Liquid; D003505:Cyclodextrins / Q000737:chemistry* / Q000528:radiation effects; D007700:Kinetics; D010777:Photochemistry; D013696:Temperature; D014466:Ultraviolet Rays
D001391:Azo Compounds; D003505:Cyclodextrins; C009850:azobenzene