An o-Phenylenediamine and MWCNT-Based Electrochemical Sensor for the Detection of Triclosan by Cyclic Voltammetry

Abstract

Selectivity and sensitivity are the two key parameters for construction of a sensor. In this work, a novel electrochemical sensor based on molecularly-imprinted composites synthesized from o-phenylenediamine (o-PD) and multiwalled carbon nanotube (MWCNT) to detect triclosan is reported. Two different sensors were developed MIC/GC and MIC/cf-MWCNT/GC. To fabricate MIC/GC, molecularly imprinted composite (MIC) was synthesized by cyclic voltammetry using o-PD, COOH-functionalized MWCNT (cf-MWCNT) and triclosan on glassy carbon (GC) electrode, following removal of surface triclosan. MIC/cf-MWCNT/GC was fabricated by synthesizing MIC on cf-MWCNT coated GC. Template removal was performed using NaOH solution. MIC/GC could detect triclosan till 40 ppb while using MIC/cf-MWCNT/GC, 10 ppb of limit of detection (LOD) was achieved. Adsorption isotherms were constructed for both the films. Langmuir adsorption isotherm gave the best fit for MIC/cf-MWCNT/GC with -ΔGads value of 54.952 kJ mol−1 indicating stronger chemisorption. To understand the role of cf-MWCNT in detection of triclosan, electrochemical band gap studies, electrochemical impedance spectroscopy, and cyclic voltammetry studies were conducted. Both the sensors were found to be efficient for detection of triclosan in the presence of interfering ions.