Amperometric sensors for detection of phenol in oilfield wastewater using electrochemical polymerization of zincon film

Abstract

Phenol and its derivatives are common organic contaminants, which are known to have adverse impacts on humans, thus the detection of phenol is very important. Herein, an amperometric sensor was fabricated based on electrochemical polymerization of zincon onto a carbon paste electrode (CPE) surface. The cyclic voltammogram of phenol on the sensor exhibited a well-defined anodic peak at 0.640 V in 0.1 mol L⁻¹ phosphate buffer solution (PBS, pH 7.0). The sensor was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Meanwhile, the influence of various parameters such as pH and scan rate on the analytical performance of the sensor was evaluated. Under the optimized conditions, the oxidation peak current was proportional to the phenol concentration change in the range from 21 μmol L⁻¹ to 292 μmol L⁻¹ and 357 μmol L⁻¹ to 922 μmol L⁻¹ with correlation coefficients of 0.9911 and 0.9966, respectively. The limit of detection was estimated to be 9 × 10⁻⁶ mol L⁻¹ (S/N = 3). Furthermore, the fabricated sensor was successfully applied to determine phenol in oilfield wastewater.