Magnetite nanoparticles were synthesized via co-precipitation of iron (II) and iron (III) salts by potassium hydroxide or ammonium hydroxide in aqueous solution at 80°C and their properties were compared. Magnetic properties of obtained magnetite nanoparticles were investigated by magnetometry method. It was shown, that precipitation by potassium hydroxide leads to decrease of saturation magnetization of obtained nanoparticles (not exceeding 40 A*m2/kg) in comparison with natural magnetite saturation magnetization (~90 A*m2/kg). At the same time, saturation magnetization of nanoparticles, obtained via co-precipitation by ammonium hydroxide was much higher (up to 60 A*m2/kg). Such degree of saturation magnetization of synthesized magnetite nanoparticles makes them promising for different medical-biological applications (enzyme and protein immobilization, cells separation and purification, DNA purification, magnetic resonance imaging contrast enhancement, targeted drug delivery, etc.).
