Use of Magnetic Microparticles for Metal Ion Sensors

Colloidal Au and Ag nanoparticles have been extensively studied as SERS substrate because they are easily prepared and yield a large Raman signal enhancement. The use of this class of SERS materials for sensor applications  can be limited by poor control over particle aggregation. This makes the colloid unstable and as a consequence can lead to poor reproducibility of the spectra. The affixation of the nanoparticles onto solid particles, such as magnetic microparticles as suggested in this study, is one way of addressing this problem. Thus, controlled particle deposition onto solid substrate looks like one of the most promising method of forming SERS substrate.  Magnetic microparticles were prepared in two steps. First step was the preparation of oleic acid coated magnetite nanoparticles which were synthesized from Fe²⁺ and Fe³⁺ salts by co-precipitation method. Second step the preparation of magnetic mPMMA-DVB particles by suspension polymerization and the last step was coating the magnetic microparticles with Au nanoparticle shell.  This Au nanoparticle coated magnetic microparticles were characterized by XRD, FT-IR and SEM.