EDAC-mediated coupling is often used for the covalent immobilization of amine-terminated proteins, DNA, or other molecules on carboxyl-functionalized PS and P(S/DVB) microspheres. See TechNote 205, Covalent Coupling, for a protocol and tips on coating optimization and QC. Carboxyl polymer microspheres are available in four standard amounts: 0.5g, 1.0g, 1.5g, and 5.0g.