Electrochemical Detection of Heavy Metal (Pb Ions) and Pharmaceutical Waste (Ciprofloxacin) in Very Low Concentration Using β‐NaFeO ₂

ABSTRACT Electrochemical techniques as a point of care analysis are drawing the researcher's attention, especially in the case of heavy metal ions (HMIs) detection. In this research, β‐NaFeO 2 was synthesized using a wet‐chemical precipitation method for the electrochemical detection of HMIs (lead‐ions in an aqueous system) and pharmaceutical waste (ciprofloxacin). The synthesized sample was characterized using an x‐ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), UV/Vis/NIR spectrophotometer, and so on. An X‐ray diffractogram confirmed the formation of an orthorhombic crystal of β‐NaFeO 2 . FTIR confirmed the presence of Na–O and Fe–O–Fe, indicating the formation of β‐NaFeO 2 . For the detection of HMIs, glassy carbon electrodes were modified using β‐NaFeO 2 , which were used as working electrodes. The effectiveness of the modified electrode was evaluated by measuring the sensing ability of the standard potassium ferrocyanide. The excellent sensing performance of the modified electrode for the lead (Pb) ions was found, as the limit of detection (LOD) was 3 × 10 −6 ppm, the limit of quantification was 1 × 10 −5 A/ppm, the sensitivity was 2.6292 A/ppm, and the linear range was 0.001–0.5 ppb. Finally, the modified electrode was also applied to sense antibiotics (ciprofloxacin) in an aqueous system.