Nano-optosensor based on titanium dioxide and graphene quantum dots composited with specific polymer for cefazolin detection

•Nano-optosensor based on the fluorescence quenching of composite fluorescent probe was developed for cefazolin detection.•Nanocomposite probes were fabricated by incorporating graphene quantum dots and titanium dioxide into a MIP.•GQDs-TiO2- MIP nanocomposite probes exhibited a highly sensitive and selective for cefazolin.•Nanoprobes provided a good recovery of spiked milk sample (85.0−97.4%) and very low limit of detection.