A novel 3D graphene–carbon nanotube network was constructed on the surface of glassy carbon electrode through a simple and effective electrodeposition approach.

The prepared 3D interpenetrated graphene-CNT network was successfully used for electrochemical determination of Methotrexate (MTX).

The improved electrochemical performance is ascribed to the large accessible surafce area of the interpenetrated 3DG network as well as its enhanced electrical conductivity by incorporating CNTs.

The proposed method can determine MTX in a wide dynamic linear range with a low detection limit.

The superior properties of the proposed sensing platform make it very suitable for electrochemical determination of MTX in pharmaceutical formulations and clinical preparations.