Fired brick microparticles assisted oxidative radical polymerization of pyrrole for electrochemical sensing: Application to the determination of ciprofloxacin and metanil yellow in food products and environmental samples

Abstract

A novel and simple hybrid sensor was constructed for the electrochemical sensing of ciprofloxacin (CPX) and metanil yellow (MEY). The sensor consists of fired brick microparticles (FB) modified with a thin film of poly(pyrrole) (PPy), which were used as a modifier for carbon paste electrode (CPE). Adding HCl to FB (which is predominantly made of Fe2O3) resulted in the release of Fe3+ ions, which aided in the oxidative polymerization of pyrrole monomer. The polar groups and aromatic rings found in the composition of PPy@FB provide more anchoring sites for adsorption of CPX and MEY, facilitating their electro-chemical oxidation. Under optimum conditions, the anodic peak currents (Ipa) showed a linear increase with increasing the concentration of CPX over the concentration range of 0.011–16.0 µmol/L and MEY in the range of 0.012–16.0 µmol/L. Limit of detections (LODs, S/N = 3) were calculated as 0.0035 µmol/L and 0.0042 µmol/L for CPX in milk and water samples, respectively. LOD for MEY in turmeric and water samples were 0.0032 µmol/L and 0.0036 µmol/L, respectively. The advantages of the as-fabricated sensor compromise greenness, simplicity, low-cost, reproducibility, sensitivity, selectivity, and adequate stability. The fabricated sensor was efficiently applied to detect CPX and MEY in different matrices including industrial water, milk, and turmeric samples with satisfactory recoveries % and low RSDs values.