title: Temperature- and pH-responsive aminopropyl-silica ion-exchange columns grafted with copolymers of N-isopropylacrylamide.
abstract: We have designed copolymers of N-isopropylacrylamide, environmentally-responsive polymers, which respond to temperature and other external stimuli. In this study, we designed and synthesized copolymers that introduced ion-exchange groups. These copolymers responded to the temperature and the pH, and the copolymer-grafted aminopropyl silica beads were used as HPLC packing materials. This stationary phase altered the properties from hydrophilic to hydrophobic and from charge to non-charge by temperature and pH changes. We studied the separations of organic acids and phenylthiohydantoin-amino acids using environmentally-responsive chromatography, and confirmed the effects of the ion-exchange groups. The elution behaviors of these samples were controlled by the temperature changes without organic solvents in the mobile phase. It was confirmed that the interactions between the solute and stationary phase could be freely controlled by the temperature and the pH. Environmentally-responsive chromatography is expected to be applicable to the separation of pharmaceuticals and biomolecules, such as peptides, proteins and nucleic acids.
authors.affiliation: Department of Physical Chemistry, Kyoritsu College of Pharmacy, 1-5-30 Shibakoen, Minato-ku, Tokyo 105-8512, Japan.
authors.forename: Chikako
authors.initials: C
authors.lastname: Sakamoto
authors.forename: Yuji
authors.initials: Y
authors.lastname: Okada
authors.forename: Hideko
authors.initials: H
authors.lastname: Kanazawa
authors.forename: Eri
authors.initials: E
authors.lastname: Ayano
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Nishimura
authors.forename: Masanori
authors.initials: M
authors.lastname: Ando
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kikuchi
authors.forename: Teruo
authors.initials: T
authors.lastname: Okano
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D011108:Polymers / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013696:Temperature
chemical_list: D000178:Acrylamides; D011108:Polymers; D012822:Silicon Dioxide; C067295:N-isopropylacrylamide