Highly sensitive MXene-based voltammetric sensor for nanomolar clozapine detection

Clozapine is vital for managing schizophrenia and other psychiatric disorders. As a potent medication with risks of severe side effects, accurate detection ensures effective treatment monitoring, patient safety, and optimization of therapeutic outcomes. Herein, niobium carbide two-dimensional transition metal carbides (Nb 2 CT x MXene) was prepared by etching niobium aluminum carbide (Nb 2 AlC), which was next partially oxidized by a hydrothermal method to niobium oxide (Nb 2 O 5 )/Nb 2 CT x and ultrasonically bound to carboxylated multi-walled carbon nanotubes (MWCNTs-COOH). It was modified onto a glassy carbon electrode for the detection of the antipsychotic drug clozapine ingested by humans. The morphology and electrochemical properties of MXene-based nanocomposite electrode were verified by scanning electron microscopy, X-ray diffractometry, Raman, cyclic voltammetry and electrochemical impedance characterization methods. The results showed that electrode responded well to clozapine solutions, with good linearity ( R 2  = 0.9979 and 0.9995) of the peak currents with clozapine concentrations (0.01–1.0 μM and 1.0–10.0 μM) and that this sensor had good immunity, repeatability, reproducibility and stability. The limit of detection was 8.38 nM and the recovery was 92.5 % ~ 106.5 % in real serum and urine samples. The MXene-based sensors offer excellent analytical performance and hold promise for cost-effective generalisation to the detection of nanomolar clozapine in a variety of clinical applications.