Synthesis of Fe3O4/Graphene/TiO2 Composites for the Highly Selective Enrichment of Phosphopeptides from Biological Samples

In this work, Fe3O4/graphene/TiO2 composites with a large surface area were designed and synthesized for the selective extraction and enrichment of phosphopeptides from biological samples. First, magnetic graphene was prepared according to our previous method. Next, we made the Fe3O4/graphene/TiO2 composite precursor using tetrabutyl titanate. Fe3O4/graphene/TiO2 composites were obtained after solvothermal and calcination treatments. We used standard protein-digestion solutions and human liver samples to test the enrichment ability of the obtained Fe3O4/graphene/TiO2 composites. The experimental results demonstrate that Fe3O4/graphene/TiO2 composites have a good phosphopeptide enrichment ability.