A new ion-exchange adsorbent (IEA) derived from Fe3O4/SiO2-GPTMS-DEAE with paramagnetic properties was prepared. Fe3O4 nanoparticles were firstly prepared in water-in-oil microemulsion. The magnetic Fe3O4 particles were modified in situ by hydrolysis and condensation reactions with tetraethoxysilane (TEOS) to form the core–shell Fe3O4/SiO2. The modified particles were further treated by 3-glycidoxypropyltrimethoxysilane (GPTMS) to form Fe3O4/SiO2-GPTMS nanoparticles. Fe3O4/SiO2-GPTMS-DEAE nanoparticles (IEA) were finally obtained through the condensation reaction between the Cl of diethylaminoethyl chloride-HCl (DEAE) and the epoxy groups of GPTMS in the Fe3O4/SiO2-GPTMS. The obtained IEA has features of paramagnetic and ion exchange properties because of the Fe3O4 nanoparticles and protonated organic amine in the sample. The intermediates and final product obtained in the synthesis process were characterized. The separation result of genomic DNA from blood indicated that Fe3O4/SiO2-GPTMS-DEAE nanoparticles have outstanding advantages in operation, selectivity, and capacity.
