Both Magnetic Classical (MC catalog codes) and Magnetic Encapsulated (ME catalog codes) microspheres are synthesized with a distribution of iron oxide crystals throughout the polymer matrix. The surfaces of encapsulated magnetic microspheres are coated to prevent iron oxide molecules from autofluorescing, while the classical version will have some exposed iron oxide. COMPEL microspheres (UMC catalog codes) are highly uniform and spherical encapsulated beads with low autofluorescence for miniaturized bioassays or separations. See the full fluorescence spectra here.nAvailable as ~1% solids (w/v) aqueous suspensions in four standard volumes: 1, 5, 10, and 100 mL.