title: Temperature-responsive stationary phase utilizing a polymer of proline derivative for hydrophobic interaction chromatography using an aqueous mobile phase.
abstract: A new method of chromatography is proposed, utilizing a thermo-responsive polymer carrying an amino acid ester residue for the stationary phase of high-performance liquid chromatography (HPLC). We have been investigating the new concept of chromatography, a temperature-responsive chromatography, using temperature-responsive poly(N-isopropylacrylamide) (PNIPAAm)-modified surface for HPLC with a constant aqueous media as the mobile phase. In this study, we designed and synthesized thermo-responsive poly(acryloyl-L-proline methyl ester) and its copolymer with N-isopropylacrylamide (NIPAAm). Homopolymers of acryloyl-L-proline methyl ester and copolymer were prepared by the reaction of radical telomerization. These polymers underwent a reversible phase transition from water-soluble forms into aggregates by changing the temperature, similar to PNIPAAm. The surface properties and functions of stationary phases modified with poly(acryloyl-L-proline methyl ester) were controlled by the external temperature. In the chromatographic system, we separated steroids and amino acids with a variety of hydrophobicities using a sole aqueous mobile phase. In contrast to a PNIPAAm-modified surface, a poly(acryloyl-L-proline methyl ester)-modified surface showed a greater affinity for hydrophobic amino acids.
authors.affiliation: Department of Physical Pharmaceutical Chemistry, Kyoritsu University of Pharmacy, 1-5-30 Shibakoen, Tokyo 105-8512, Japan. kanazawa-hd@kyoritsu-ph.ac.jp
authors.forename: Hideko
authors.initials: H
authors.lastname: Kanazawa
authors.forename: Eri
authors.initials: E
authors.lastname: Ayano
authors.forename: Chikako
authors.initials: C
authors.lastname: Sakamoto
authors.forename: Reiko
authors.initials: R
authors.lastname: Yoda
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kikuchi
authors.forename: Teruo
authors.initials: T
authors.lastname: Okano
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D011392:Proline / Q000737:chemistry*; D013256:Steroids / Q000302:isolation & purification; D013696:Temperature; D014867:Water
chemical_list: D013256:Steroids; D014867:Water; D011392:Proline