Light-Transmitting Measurements through Starch-Coated Cobalt Ferrite Ferrofluids Exposed to an External Magnetic Field

The light-transmitting measurements at the 655 nm wavelength have been performed through starch-coated cobalt ferrite ferrofluids synthesized by well-established synthetic methods, i.e., coprecipitation, mechanochemical, ultrasonically assisted coprecipitation, microemulsion, and microwave-assisted hydrothermal syntheses, exposed to an external magnetic field of 200–400 mT. The investigated samples can be divided into the two groups. The first is where the samples showed higher rate of agglomeration and sedimentation effects. The group of samples synthesized by microemulsion, microwave-assisted hydrothermal method, and mechanochemical method showed less pronounced rate of chain formation. Such measurements present good method for the preliminary selection of possible magnetic resonance imaging (MRI) contrast agents between differently synthesized ferrite suspensions.