After EDC/NHS coupled conjugation of IONPs ( 50 nm) and antibody, I got unbound antibodies, unbound IONPs and Antibody-IONPs conjugates in the solution. Using magnetic separator I am able to separate unbound antibodies but I also want to separate unbound IONPs, to get purified Ab-IONPs conjugates which are necessary for my further experiments because the presence of unbound IONPs will give the false signal.Can anyone suggest me the most facile methods to do so? As my lab is not that much rich.