||Poly(sucrose-co-epichlorhydrin), CAS #: 72146-89-5, often called Ficoll, is labeled with fluorescein. Ex/Em wavelength 494/518 nm. Purity: >95% lyophilized powder. Degree of substitution: 1 mol % substitution and at least one dye molecule per polymer. FicollÂ® is a registered trademark of GE Healthcare. Literature: 1) Splenic outer periarterial lymphoid sheath (PALS)â€‹: an immunoproliferative microenvironment constituted by antigen-â€‹laden marginal metallophils and ED2-â€‹positive macrophages in the rat, Cell and tissue research, 1989, 257(3), 459-70.