Modified carbon paste electrode based on nanotechnology for determining phenol in the liquid solutions by cyclic voltammetry and comparing to high-performance liquid Chromatography

In this paper, phenol was determined in a liquid solution based on fabricating a phenol-selective electrode by cyclic voltammetry (CV). The carbon paste electrode was modified with nickel oxide nanoparticles (NiO) which were doped with nitrogen carbon quantum dots (NCQD) as the NiO-NCQD nanocomposite. The modified carbon paste electrode was manufactured in a laboratory at optimized pH. In the optimized condition, the best results were created at pH 7.0 and 4.0 using KH2PO4 buffer solution. By voltammetry, the voltage was optimized, and the best value for the voltages was obtained at 0.04166V and 0.05991V for pH 4 and 7, respectively. The scan rate (SR) was studied and the best SR was achieved at 100 mv s-1 for both pH. Due to the results, a wide linear dynamic range between 10 to 1000 μM was obtained. Also, the standard phenol solution was analyzed by high-performance liquid chromatography (HPLC). The retention time (RT), the wavelength maximum (λ max: nm), and the peak area equation of HPLC were achieved at 2.982 min, 270 nm, and (Area=40420CPhenol+ 43.557), respectively by the concentration range of 0.1-5.0 mg L-1. The  NiO-NCQD adsorbent determined phenol by cyclic voltammetry and compared it with the HPLC technique.