Effect of citric acid content on magnetic property of magnetite particles for detecting virus

Masami Hashimoto, Seiji Takahashi, Koichi Kawahara, Daisaku Yokoe, Takeharu Kato, Tomoyuki Ogawa, Masakazu Kawashita, Hiroyasu Kanetaka

Research output: Contribution to journalArticlepeer-review


The magnetic particles with high saturation magnetization and superparamagnetism are needed to detect highly sensitive viruses. The magnetic property of magnetite (Fe3O4) particles synthesized by spray pyrolysis and a subsequent heating process depended on the citric acid content. The magnetic particles consist of nano-sized Fe3O4 crystallite about 10 nm in diameter and the decomposed C with high dispersion. The edge-to-edge separation of the crystallites is about 8 nm. As a result, the superparamagnetic Fe3O4 particles can be synthesized. The saturation magnetization of the synthesized beads (51 A·m2 kg-1) is much higher than that of commercial magnetic microbeads (17 A·m2 kg-1), and the coercive force is 0.24 kA m-1. Superparamagnetism can likely be attained because of the high dispersion of Fe3O4 crystallites below 10 nm in diameter. The Fe3O4 crystallites did not magnetically interact with each other. These unique Fe3O4 particles may hold promise as magnetic particles for enzyme immobilization due to the high possibility of antibody bonding and the ease of separation by magnetic fields.

Original languageEnglish
Pages (from-to)882-888
Number of pages7
JournalJournal of the Ceramic Society of Japan
Issue number11
Publication statusPublished - 2022 Nov 1


  • Citric acid
  • Micrometer-sized particle
  • Spray pyrolysis
  • Superparamagnetic FeO

ASJC Scopus subject areas

  • Ceramics and Composites
  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry


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