Nano chitosan derivative and preparation method and application thereof

The invention relates to the technical field of nano materials in biomedicine. Specifically, the invention provides a nano chitosan derivative, a preparation method and a method of applying the nano chitosan derivative to enrich and purify phosphopeptide highly selectively and specifically. The preparation method comprises the following steps: the chitosan is dissolved in diluted acid and then is mixed with glycidyl methacrylate or glycidyl acrylate to carry out self-polymerization and grafting reaction, thus obtaining a nano composite medium chitosan derivative with active epoxy groups; the composite medium and iminodiacetic acid or aminotriacetic acid or ethylenediamine triacetic acid carry out ring-opening addition reaction to obtain a nano medium chitosan derivative with carboxylic active functional groups; and finally the medium and transition metal ions such as Fe3+, Ti4+, Zr4+, Ga3+ and the like carry out chelation to prepare the final nano chitosan derivative. The nano chitosan derivative has high spe