Enhancing of ofloxacin oxidation current through the overvoltage position displacement using carbon paste electrode modified by silver particles: Analytical application in water

In this study, a modified carbon paste electrode with silver particles (Ag–CPE) was used for ofloxacin (OFL) detection with enhanced over-potential for low concentrations. The incorporation of silver particles on carbon paste was confirmed by scanning electron microscopy. Electrochemical behavior of ofloxacin at carbon paste electrode (CPE) and Ag–CPE was studied using cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy. The OFL interaction with Ag⁺ was derived from the oxidation of silver during anodic scan has been investigated under different conditions. The strong binding affinity of Ag⁺ with 1.0 ​× ​10⁻⁵ ​M OFL resulted in the upward shift of the OFL potential, which shifted potential from 0.85 to 0.95 ​V. The modification of carbon paste electrode by silver microparticles has enhanced the oxidation current with over-potential of OFL at low concentrations without a decrease of the current. The influence of the sweeping potential range on OFL oxidation was optimized. The calibration curve for ofloxacin at Ag–CPE is linear in the range from 4.0 ​× ​10⁻⁶ to 1.0 ​× ​10⁻³ ​M, and the detection limit was 9.47 ​× ​10⁻⁷ ​M. Possible effects of inorganic ions and organic substances were investigated but did not cause any significant interferences. Furthermore, the repeatability, reproducibility, and stability of the present sensor were done with satisfactory results. The proposed method was successfully applied to OFL determination in tap water samples.