A Molecularly Imprinted Composite-based Novel Electrochemical Sensor Using o-Phenylenediamine, Molybdenum Nanoparticle, and Multiwalled Carbon Nanotube for Triclosan Detection from Water

A novel electrochemical molecularly imprinted composite (MIC)-based sensor for detection of triclosan was developed. MIC was synthesized from o-phenylenediamine (o–PD), -COOH functionalized multiwalled carbon nanotube (cf-MWCNT), and triclosan by cyclic voltammetry on molybdenum nanoparticle (Mo-NP) embedded cf-MWCNT (Mo-cf-MWCNT) coated glassy carbon (GC) electrode, following removal of surface triclosan to form MIC/Mo-cf-MWCNT/GC. In our earlier work, two novel electrodes MIC/cf-MWCNT/GC and MIC/GC were fabricated. The presence of cf-MWCNT coating substrate on GC in MIC/cf-MWCNT/GC had improved the sensing performance than MIC/GC since presence of this substrate had decreased the electrochemical band gap (E_g) and increased Debye length (λ_d), Gibb’s free energy of adsorption (− ΔG_ads), electrochemical surface area (A_e), and surface redox site concentration (C*). Therefore, further improvement in sensing performance can be carried out by utilizing Mo-NP in the cf-MWCNT coating substrate using MIC to be the sensing material. This novel electrode (MIC/Mo-cf-MWCNT/GC) provided a limit of detection (LOD) of 900 ppt of triclosan, which was lower than the LOD achieved by using MIC/cf-MWCNT/GC (10 ppb) and MIC/GC (40 ppb). Adsorption isotherm was constructed for MIC/Mo-cf-MWCNT/GC delivering − ΔG_ads value of 59.049 kJ/mol indicating stronger chemisorption. To understand the role of Mo-cf-MWCNT in detection of triclosan, cyclic voltammetry, electrochemical impedance spectroscopy, and electrochemical band gap studies were conducted. This MIC/Mo-cf-MWCNT/GC showed good selectivity towards triclosan in presence of interfering ions.