Contamination of antibiotics in water is a major cause of antibiotic resistance (ABR) in pathogens that endangers human health and food security worldwide. Ciprofloxacin (CIP) is a synthetic fluoroquinolone (FQ) antibiotic and is reportedly present in surface water at a concentration exceeding the ecotoxicological predicted no-effect concentration in some areas. This study fabricated a CIP sensor using an electropolymerized molecularly imprinted polymer (MIP) of polyaniline (PANI) and poly(o-phenylenediamine) (o-PDA) with CIP recognition sites. The MIP was coated on a reduced graphene oxide (rGO)modified glassy carbon electrode (rGO/GCE) and operated under a differential pulse voltammetry (DPV) mode for CIP detection. The sensor exhibited an excellent response from 1.0 × 10 −9 to 5.0 × 10 −7 mol L −1 CIP, showing a sensor detection limit and sensitivity of 5.28 × 10 −11 mol L −1 and 5.78 μA mol −1 L, respectively. The sensor's sensitivity for CIP was 1.5 times higher than that of the other tested antibiotics, including enrofloxacin (ENR), ofloxacin (OFX), sulfamethoxazole (SMZ), and piperacillin sodium salt (PIP). The reproducibility and reusability of the sensor devices were also studied.

Ciprofloxacin (CIP) is widely utilised to treat bacterial infections. Currently, CIP is present in water sources at higher concentrations, thus necessitating close monitoring. This study developed electrochemical nano-sensors based on molecularly imprinted polymer (MIP) and reduced graphene oxide (rGO) composites to detect CIP. rGO served as the loading platform for MIP immobilisation on a glassy carbon electrode (GCE). A copolymer thin film, comprised of polyaniline copolymerized with o-phenylenediamine (PAni-co-PDA) was obtained by electro-polymerisation utilizing cyclic voltammetry (CV) under suitable conditions. The performance of the modified GCE was examined utilizing CV mode in a hexacyanoferrate electrolyte as an electrochemical probe. The PAni-co-PDA/rGO-modified GCE exhibited enhanced improvement and efficient electrocatalytic behaviour in the oxidation of CIP with relatively high sensitivity and stability. The sensor was operated in differential pulse voltammetry (DPV) mode. Our best results revealed good linearity response to CIP in the range of 0.001–10.0 μM with an R-squared of 0.949, a detection limit of 0.09 μM (3.3 SD/S), and the calibration plot of ΔI minus the logarithm of the CIP concentration exhibited a sensitivity of –1.521. The sensor demonstrated a conductive polymer-based device that can be utilised for rapid CIP determination in pharmaceutical samples and biological fluids.