▎ 摘　　要

NOVELTY - Guanidine functionalized graphene compound of (I), is new. USE - Guanidine functionalized graphene compound used as solid phase extraction material and used in the selective enrichment of phosphorylated peptides. DETAILED DESCRIPTION - Guanidine functionalized graphene compound of formula (I), is new. G=graphene substrate; and n=2-8. An INDEPENDENT CLAIM is included for a method for preparing guanidine functionalized graphene compound, which involves: (A) taking oxidized graphene surface with carboxyl group to obtain graphene acyl chloride and then burning the obtained material with 2-8C diamino compound (II) to obtain compound (III); (B) dispersing the compound (III) in water and then adding ortho-methylisourea to the dispersed material; and (C) heating the obtained material to obtain the guanidino functionalized graphene compound (I), where the pH of reaction solution is 10-12.