A sensitive molecularly imprinted poly(o-aminophenol)-based electrochemical sensor for propiconazole in food samples using reduced graphene oxide- chitosan composite

Abstract

The presence of propiconazole (PRO), an endocrine disruptor and persistent triazole fungicide, in surface water, demanded the development of simple, and sensitive sensors. A reusable molecularly imprinted polymer (MIP)-based electrochemical sensor was developed for the sensitive detection of PRO using poly (o-aminophenol) and an electrochemically reduced graphene oxide-chitosan (ERGO-CS). The poly o-aminophenol recognition receptors were electrogenerated on the surface of an ERGO-modified glassy carbon electrode in the presence of PRO as a template. The ERGO-CS film improved the electrode surface area which loads a high density of PRO-imprinted sites on the electrode surface. Scanning electron microscopy, voltammetric, and impedance techniques demonstrated the successful fabrication of the MIP sensor. The drop in the peak current and increment in the charge transfer resistance of the redox probe [Fe(CN)₆]^3−/4− upon selective recognition of RPO to the MIP sensor are employed as the sensor responses.

Under the optimal parameters of monomer type, monomer to target molar ratio, electropolymerization conditions, and the removal method, the MIP sensor achieved two linear responses over the PRO concentration range of (0.01 pM to 1 pM) and (1 pM to 10 µM) with a limit of detection of about 0.008 pM for DPV and EIS methods. The MIP sensor exhibited superior selectivity against the interferent pesticides. The PRO-MIP sensor exhibited acceptable reproducibility and can be regenerated up to 6 cycles. The MIP sensor has shown satisfactory accuracy for the quantification of PRO in soil, agriculture water, wheat flour, milk, and cucumber samples with good recovery 87.59 % to 117.94 %) and RSD of 1.79 to 14.98 %. The MIP sensor offers a promising alternative for monitoring PRO in environmental samples.