Magnetic polymer particles have been widely used in a large number of biotechnology and biomedicine applications (1–3). In modern pharmacy, basic investigations for the manufacturing and characterization of new dosage forms are frequently performed using magnetic fillers and drug carriers, which can be classified as the artificial sources of magnetic fields. These sources are most typically based on magnetite, iron (III) γ-oxide, and barium ferrite (4).
Magnetite is an iron ferrite with the general formula Fe3O4 and a crystal lattice of the inverse spinel type. The octahedral crystal structure is a characteristic feature of magnetite. In the inverse spinel structure, the tetrahedral sites are occupied by Fe3+ ions and the octahedral sites are shared between equal amounts of Fe3+ and Fe2+ ions (5). Part of the qualitative analysis of magnetic components in biological objects may be performed using the techniques of superconducting quantum interference device magnetometry and ferromagnetic resonance (6).
An important point in the preparation of magnetic polymer particles, especially for biomedical applications, is the evaluation of the magnetic content (7). The quantitative composition determination of magnetic substances is commonly performed by a variety of methods such as titration (8), thermogravimetric techniques (7,9), and X-ray diffraction (10). Nowadays, spectrophotometric methods have often been applied for even metal trace determination (11), due to advantages such as accuracy and good precision, low cost, and simple operation.
The objective of the present work is to report a simple, yet accurate, manner for the determination of the magnetite content in magnetic polymeric microparticles, by the association of spectrophotometry, via the complexation of iron ions with sulfossalycilic acid dihydrate (SSA), and magnetometry.