An affinity matrix for the small-scale immunomagnetic separation and purification of rabbit IgG’s. Goat Anti-Rabbit IgG is covalently coupled to a nonporous superparamagnetic particle. This secondary antibody binds the heavy chain of all rabbit IgG subclasses and is suitable for immunoassays that employ a rabbit IgG primary polyclonal antibody. Cell separations and sorting can be accomplished using a rabbit IgG antibody to defined cell surface antigens.