Aqueous chromatography system using pH- and temperature-responsive stationary phase with ion-exchange groups

Eri Ayano, Kyoko Nambu, Chikako Sakamoto, Hideko Kanazawa, Akihiko Kikuchi, Teruo Okano

Research output: Contribution to journalArticlepeer-review

57 Citations (Scopus)


We report on the development of a novel analytical HPLC technique of nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, ketoprofen and naproxen, with an isocratic aqueous mobile phase. In this study, we designed a new pH- and temperature-responsive copolymer of N-isopropylacrylamide (NIPAAm), butyl methacrylate (BMA) and N,N-dimethylaminopropylacrylamide (DMAPAAm). The copolymer was modified with cross-linked poly(NIPAAm-co-BMA-co-DMAPAAm) (IBD) hydrogel on to aminopropyl silica beads, and the products were evaluated as HPLC packing materials for an ion-exchange- and temperature-responsive chromatography. The property of the surface of the stationary phase was altered from hydrophilic to hydrophobic, and from charged to non-charged by changes in the temperature and pH. In addition, it is possible that ion-exchange groups can appear or be hidden on the polymer chain surface by temperature changes. The interactions of NSAIDs with this stationary phase were controlled by the temperature and the pH with a constant aqueous mobile phase. PH- and temperature-responsive chromatography is expected to be useful for the separation of pharmaceuticals and biomolecules.

Original languageEnglish
Pages (from-to)58-65
Number of pages8
JournalJournal of Chromatography A
Issue number1-2
Publication statusPublished - 2006 Jun 30


  • HPLC
  • Ibuprofen
  • Ketoprofen
  • NSAIDs
  • Naproxen
  • Poly(N-isopropylacrylamide)
  • pH- and temperature-responsive chromatography

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Organic Chemistry


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