Ferriferrous oxide magnetic microspheres(MSs)were prepared via solvothermal route.The so-obtained MSs were modified by(3-mercapto-propyl)trimethoxysilane(MPS)in mythylbenzene to give birth of the ferriferrous oxide with thiol group(Fe3O4-SH)microspheres,which can absorb Ni 2+to form Fe3O4-SH-Ni 2+.The amount of thiol group of Fe3O4-SH was tested to be 333.54μg/mg by means of DTNB method.After chelating Ni 2+ions,Fe3SH-Ni 2+MSs were used to enrich and purify histidine-tagged(His-tagged)proteins directly from...