Carboxyl Super Mag (50 nm) are hydrophilic magnetic beads with carboxylic acid groups. These surface groups allow covalent amide bond formation to proteins/peptides via primary amine (NH2) groups. Oligonucleotides, antibodies or other ligands with amine groups can be easily coupled to the beads. Activation through carbodimide is required. With large surface area, excellent colloidal stability and unique surface coating, the Carboxyl Super Mag (50 nm) exhibit high binding capacity and low non-specific binding of protein or nucleic acids.