Changes of structural, magnetic and spectroscopic properties of microencapsulated iron sucrose nanoparticles in saline.

The structural and physical properties of microencapsulated iron sucrose and their changes upon dissolution in saline were tested. For the undissolved sample, calcium alginate microcapsules with irregular shapes were registered via scanning electron microscopy, inside which core-shell nanoparticles were identified by transmission electron microscopy micrographs. Magnetic studies (DC and AC) performed on the undissolved sample revealed the presence of a low temperature blocking process (<T _B> ≈ 10 K), and confirmed its superparamagnetic state between 70- 250 K. X-ray photoelectron spectroscopy and Raman studies showed a varied composition of the undissolved sample in which organic compounds and SiO₂ are the major phases, while the iron phase was recognized as iron oxyhydroxide (FeOOH) (most probably the α polymorph). The dissolution procedure had significant influence on structural and physical properties of the investigated compound, such as lowering of the blocking temperature with the dissolution time. Electron paramagnetic resonance (EPR) studies performed on the completely dissolved sample revealed that some of the Fe³⁺ ions became paramagnetic, while the rest remained exchange coupled into clusters. The nonintentional manganese contamination was determined using EPR in the completely dissolved sample.