Patent ID: 8366916

Claim:
A method for preparing a magnetic nanoparticle complex, comprising: preparing a pre-ligand comprising: at least one amino group; and at least one carbamate group or dithiocarbamate group; associating the pre-ligand with a magnetic nanoparticle; and modifying the pre-ligand associated with the magnetic nanoparticle to form a ligand associated with the magnetic nanoparticle, the ligand comprising: a functional group configured to combine with an acid component in an oil or a conjugate base of the acid component; wherein: the functional group comprises an amine group configured to combine with an acid component, or an ammonium group configured to combine with the conjugate base of the acid component; a nitrogen atom of the ammonium group is bound with at least one hydrocarbon group; the hydrocarbon group is a substituted or unsubstituted C 8 -C 20 alkyl, cycloalkyl, alkenyl, alkynyl, aryl, or aralkyl group; and the ligand associated with the nanoparticle is a magnetic nanoparticle complex.