An electrochemical sensor for the detection of pesticides based on the hybrid of manganese phthalocyanine and polyaniline
By Aky
Published in Sensors and Actuators B: Chemical
2019
Abstract
A mimic enzymeless electrochemical sensor (M-Eless-ES) based on the terminal alkynyl substituted manganese phthalocyanine (MnPc-TA) and 4-azido polyaniline (N3-PANI) hybrid was constructed and tested as a selective and sensitive pesticide sensor. A new electrode modification technique, solid state electropolymerization of a film, was developed for the preparation of ITO/MnPc-TA/N3-PANI electrode as M-Eless-ES for the first time in this study. During construction of ITO/MnPc-TA/N3-PANI electrode, MnPc-TA was firstly deposited on indium tin oxide coated glass substrate (ITO) with Langmuir Blodgett (LB) technique. Then 4-azidoaniline (N3-ANI) was bonded to the terminal alkynyl substituents of MnPc-TA (ITO/MnPc-TA/N3-ANI) with click chemistry (CC) and finally ANI groups of the solid MnPc-TA/N3-ANI hybrid film was electropolymerized on ITO surface to form ITO/MnPc-TA/N3-PANI electrode. The modified electrode was characterized with square wave voltammetry (SWV), X-ray diffraction (XRD), scanning electron microscope (SEM), and fourier transform infrared (FT-IR). Finally, ITO/MnPc-TA/N3-PANI electrode was tested as potential M-Eless-ES for the fenitrothion, eserine, and diazinon via SWV technique. Different voltammetric responses were observed for each pesticide. Observation of a new redox peak due to the interaction of the electrode with the fenitrothion indicated its distinct selectivity for this pesticide. The limit of detection (LOD) (0.049 ?mol dm?3 for fenitrothion, 0.088 ?mol dm?3 for eserine and 0.062 ?mol dm?3 for diazinon), wide linear ranges, and especially higher selectivity were observed with ITO/MnPc-TA/N3-PANI which are the basic requirements for the practical applications for the pesticide sensing. Reproducibility, easy of construction, and stability of the electrode are other superior advantages. As a real sample application, ITO/MnPc-TA/N3-PANI sensor was successfully employed for determining the fenitrothion residue in rosehip sample.