A Novel Electrochemical Sensor for the Determination of the Non-Small Cell Lung Cancer Drug Erlotinib Using p-Type Cuprous Delafossite CuBO2 Nanosheets and Graphene Quantum Dots

This study presents the development of a novel electrochemical sensor for the determination of erlotinib (ERT), a non-small cell lung cancer drug, using a modified glassy carbon electrode composed of p-type cuprous delafossite CuBO2 nanosheets and graphene quantum dots. The CuBO2 was synthesized via a hydrothermal method and characterized using X-ray diffraction and scanning electron microscopy. The modified electrode exhibited enhanced electrocatalytic activity towards ERT oxidation, which caused a significant increase in oxidation current and shifted the oxidation potential to more negative values. The sensor demonstrated a linear response to ERT concentrations ranging from 1.0 to 60.0 µmol/L, with a detection limit of 0.5 µmol/L. The electrode also showed excellent stability, reproducibility, and selectivity, making it suitable for real sample analysis. The proposed method was successfully applied to determine ERT in human serum samples.