▎ 摘　　要

We report on electron paramagnetic resonance and nuclear magnetic resonance study of graphene oxide produced by the Hummers method. We show that this compound reveals isolated Mn2+ ions, which originate from potassium permanganate used in the process of the sample preparation. These ions are likely anchored to the graphene oxide planes and contribute to the H-1 and C-13 spin-lattice relaxation.