Electrochemical measurement of fleroxacin using a NiMoO4 micro-rods/carboxylated multi-walled carbon nanotube composite sensor

NiMoO 4 micro-rods/MWCNT-COOH composite first applied for FLX detection. • Low LOD (0.012 μM), wide range (0.05–20  μM), high sensitivity (μA μM −1 ). • Enrichment via electrostatic attraction, H-bonding, and π‑π stacking (adsorption-controlled). • Good anti-interference, 82% stability over 30 days, recoveries 94–104% in real samples. • Structural and functional complementarity (conductivity + catalysis) of the composite. Fleroxacin (FLX), a commonly utilized fluoroquinolone antibiotic, has been identified as a significant environmental and human health hazard due to its presence and accumulation in the environment. In this study, an electrochemical sensor employing a NiMoO 4 /MWCNT-COOH composite material was devised for the highly selective and highly sensitive detection of FLX in environmental water samples. The nickel molybdate microrod/carboxylated multiwalled carbon nanotube composites (NiMoO 4 /MWCNT COOH) synergistically combines the catalytic properties of NiMoO 4 with the exceptional conductivity and dispersibility of MWCNT-COOH, thereby enhancing electron transfer rates and the effective electroactive surface area. The sensor demonstrated a favorable linear response within the concentration range of 0.05–20 μM, with a limit of detection of 0.012 μM, a sensitivity of 2.988 μA μM −1 , good anti-interference capabilities, and sustained stability (signal retention rate of 82% over 30 days). Furthermore, spiked recovery experiments conducted in authentic water samples (tap water, lake water, serum and bean sprout) yielded recoveries ranging from 94.04% to 103.8% and the relative standard deviations (RSDs) are less than 5%, affirming the method’s suitability for the reliable analysis of FLX in complex matrices. This approach offers a robust sensing platform for environmental antibiotic monitoring.