Carboxyl magnetic beads are superparamagnetic nano magnetic beads, which surface was carboxyl functional groups.After activation (eg.Actived by EDC and Sulfo-NHS) it can conjugated with primary amine from Nucleic acid, Protein, Antibody or other molecular, form stable amide bond. The coupled beads can be separated from the solution by Magnetic separation device, and used for downstream purification and separation tests in directly.