Temperature-responsive mixed-mode column containing temperature-responsive polymer-modified beads and anionic polymer-modified beads

Kenichi Nagase, Maria Watanabe, Fumihiko Zen, Hideko Kanazawa

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)


We developed temperature-responsive mixed-mode columns packed with poly(N-isopropylacrylamide) (PNIPAAm)-modified beads and poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS)-modified beads in various ratios. The PNIPAAm-modified silica beads and PAMPS-modified silica beads were prepared by surface-initiated atom transfer radical polymerization of N-isopropylacrylamide and 2-acrylamido-2-methylpropane sulfonic acid, respectively. We confirmed polymer modification of the silica beads by CHN elemental analysis, FTIR, zeta-potential measurements, and SEM. To determine the column separation efficiency, we examined the elution behaviors of cold medicine active ingredients and monoamines from each column. Analyte separation occurred on columns with PNIPAAm to PAMPS ratios of 1:20 and 1:10, whereas a column containing only PNIPAAm-modified beads did not retain the analytes. The analytes were retained on the columns through hydrophobic and electrostatic interactions with PNIPAAm and PAMPS, respectively. The separation performance improved with increasing column temperature because of dehydration of PNIPAAm and enhancement of hydrophobic interactions at elevated temperatures. The mixed-mode columns will be useful for separating basic bioactive compounds because the retention of analytes can be modulated by changing the column temperature and the composition.

Original languageEnglish
Pages (from-to)220-229
Number of pages10
JournalAnalytica Chimica Acta
Publication statusPublished - 2019 Nov 4


  • Bioseparation
  • Poly(N-isopropylacrylamide)
  • Temperature responsive chromatography
  • Thermoresponsive polymer

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy


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