Maryam Roostaee - Department of Analytical Chemistry, Faculty of Chemistry, University of Kashan, Kashan, I.R. Iran
Mehdi Shabani-Nooshabadi - Department of Analytical Chemistry, Faculty of Chemistry, University of Kashan, Kashan, I.R. Iran

In this work we describe a novel NiO nanoparticles room temperature ionic liquid (RTIL) modified carbon paste electrode as a high sensitive sensor for voltammetric determination of 4-chlorophenol (4-CP) in environmental samples. The sensor exhibits an enhanced effectiveness for the electro-oxidation of 4-CP in aqueous solution. The oxidation peak potential for this matter at a surface of the ionic liquid (n-hexyl-3-methylimidazolium hexafluoro phosphate)NiO/NPs carbon paste electrode appeared at 610 mV that was about 90 mV lower than the oxidation peak potential at the surface of the traditional carbon paste electrode (CPE) under similar condition. The mechanism of the electro-oxidation process on the surface of the modifiedelectrode was analyzed. Square wave voltammetry (SWV) was applied as a very sensitive electrochemical method for the determination of sub-micro-molar amounts of 4-CP. The prepared modified electrode shows several advantages such as simple preparation method, highstability, high sensitivity, and excellent catalytic activity, long-term stability and remarkable voltammetric reproducibility for eletrooxidation of 4-CP. The proposed sensor was successfully applied for the determination of 4-CP in environmental samples. The XRD pattern of NiO/NPs,in the 2θ range of 10–90°, is shown in Fig. 1A. Typical TEM micrograph of the NiO/NPs is shown in Fig. 1B.

4-chlorophenol; NiO nanoparticle, Ionic liquids, Voltammetric analysis