Ultra-sensitive electrochemical detection of glutamate based on reduced graphene oxide/Ni foam nanocomposite film fabricated via electrochemical exfoliation technique using waste batteries graphite rods

•Electrochemically exfoliated ultra-thin layers of graphene from waste-discharged battery is successfully used in fabricating a biosensor for the detection of glutamate.•The rGO/NiF glutamate biosensor exhibits a linear response within the range of 5–300 µM.•The biosensor exhibits an ultra-high sensitivity with a limit of detection (LOD) ∼0.1 µM and a shelf-life of about ten weeks.