BiMoO/MWCNTs-COOH/GCE electrochemical probe for ultrasensitively and selectively detecting antibiotic norfloxacin.

Antibiotics have emerged as a class of contaminants of concern globally, raising widespread worry and unease, primarily because of their inappropriately use and endless migration in food chains. Electrochemical ultrasensitive and selective determination of norfloxacin (NOR) using bismuth-based bimetallic salt bismuth molybdate (BiMoO) and carboxylated multi-walled carbon nanotube (MWCNTs-COOH) hybrid electrode as sensing platforms is presented hereby. The electrocatalytic ability of the electrodes was verified to be enhanced by the synergy effect of both BiMoO and MWCNTs-COOH using cyclic voltammetry and electrochemical impedance spectroscopy. Linear scan voltammetry was applied to detect NOR. The oxidation peak current was linearly correlated with NOR concentration of 0.03-10 μM and the low limit detection of the optimized method was 6.7 nM (S/N = 3). In addition, it was verified that BiMoO/MWCNTs-COOH/GCE probe had good stability, reproducibility, repeatability and selectivity. The spiked recovery method for NOR in milk and lake water samples showed recoveries of 94.8 - 96.9% and 90.2 - 98.3%, respectively, which can be used to determine NOR in real samples with high sensitivity. The preparation of BiMoO/MWCNTs-COOH/GCE provides a new prototype for probing NOR detection at nanomolar concentration and safeguarding antibiotic contamination in environmental and food chains.