Application of nickel-doped graphene nanotubes to modified GCE as a sensitive electrochemical sensor for the antipsychotic drug clozapine in spiked human blood serum samples

Abstract Clozapine (CLZ) is one of the most vital medications for managing schizophrenia, and the timely measurement of CLZ levels has been recognized as an obstacle to the wider use of CLZ. Herein, for the first time, nickel-doped graphene nanotubes (Ni@GRNT) were used to construct an electrochemical CLZ sensor by drop coating Ni@GRNT suspension on a glassy carbon electrode. The Ni@GRNT was synthesized and characterized using X‐ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The electrochemical behavior and influence of different physicochemical factors of sensing electrodes were investigated by using cyclic voltammetry, EIS technique, and differential pulse voltammetry techniques. Also, the catalytic rate constant ( k cat ) and the transfer coefficient ( α ) were calculated. The modified electrode illustrated satisfactory linear range, detection limit (LOD), reusability, and reproducibility results. At optimal experimental conditions, measurements can be performed at a broad linear dynamic range of 0.3 nmol L −1 –60.0 μmol L −1 CLZ and with a LOD of 0.1 nmol L −1 . The sensitivity value was estimated to be 3.06 μA µmol L −1 cm −2 . Ultimately, this platform was successfully used for CLZ sensing in spiked human blood serum and tablet samples with an accuracy of > 93%. Graphical abstract