Synthesis and characterization of amino-functionalized single magnetic core–silica shell composites

The thermal decomposition approach, reverse micro-emulsion system and surface modification technique had been successfully used to synthesis single magnetic core Fe 3 O 4 @Organic Layer@SiO 2 –NH 2 complex microspheres . The magnetization of the magnetic microspheres core could be easily tuned between 28 and 56   emu/g by adjusting the amount of 2-mercaptobarbituric acid. It was found that the Organic Layer to some extent had a protective effect on avoiding Fe 3 O 4 being oxidized into Fe 2 O 3 . Each Fe 3 O 4 @Organic Layer microsphere could be coated uniformly by about 30   nm of silica shell. The average diameter of the Fe 3 O 4 @Organic Layer@SiO 2 composites was about 538   nm. The saturation magnetization of the Fe 3 O 4 @Organic Layer@SiO 2 complex microspheres was 12.5% less than magnetic microspheres cores. The Fe 3 O 4 @Organic Layer@SiO 2 –NH 2 composites possessed a huge application potentiality in specificity enriching and separating biological samples.