Zinc and Sulfur Codoped Iron Oxide Nanocubes Anchored on Carbon Nanotubes for the Detection of Antitubercular Drug Isoniazid

Zinc and sulfur codoped iron oxide nanocubes on functionalized multiwalled carbon nanotubes (Zn@S-FeNC/f-CNTs) were synthesized by a conventional hydrothermal (HT) route followed by ultrasonication, and the synthesized nanocomposites were used for the sensitive and selective detection of isoniazid (INZ). The morphological, structural, and electrochemical properties of the composite were well characterized. The application of the screen-printed carbon electrode modified with Zn@S-FeNC/f-CNT for the detection of antibiotic drug INZ (for the treatment of tuberculosis, TB) by employing voltammetric and amperometric techniques. The composite served as an outstanding electron (e–)-transfer mediator for INZ oxidation. Under optimum conditions, the modified electrode showed a distinct response for voltammetric and amperometric analyses toward INZ detection, yielding low detection limits of 5.01 and 8.54 nM, respectively. The calculated charge-transfer rate constant (ks) was 1.6 × 10–6 cm s–1, while the electrochemical active surface area was estimated to be 0.157 cm2. The fabricated sensor exhibited good selectivity, long-term stability, and high reproducibility. The sensor has been further used to examine human serum and urine samples with good recovery.