Poly(methylene blue)-Based Electrochemical Platform for Label-Free Sensing of Acrylamide

The present work reports the electrochemical sensing of acrylamide (AM) using a poly(methylene blue)-modified glassy carbon electrode (PMB/GCE) where PMB functions as an electrochemical reporter. PMB was prepared by electrochemical polymerization of methylene blue. Electrochemical sensing of AM was facilitated by the interaction between AM and PMB. Further the interaction between AM and PMB was investigated using ultraviolet-visible (UV-vis) spectroscopy and Raman analysis. The surface morphology was confirmed by atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM) analyses. PMB/GCE was further characterized by X-ray photoelectron spectroscopy (XPS), and the electrochemical performance was assessed using cyclic voltammetry and differential pulse voltammetry. Cyclic voltammetry analysis showed a decrease in current at the redox center of PMB upon addition of AM. The association constant and binding number of AM with PMB/GCE were calculated using differential pulse voltammetry and found to be 8.9 × 10⁶ M^-1 and 0.64 (∼1), respectively. The results indicated a strong interaction of AM on the PMB/GCE surface. Further, chronocoulometry analysis of PMB/GCE in the presence of AM showed a decrease in charge due to the interaction of AM with PMB. Under optimized conditions, PMB/GCE exhibited a decrease in current proportional to the concentration of AM in the range of 0.025-16 μM with sensitivity and detection limit 0.252 μA nM^-1 and 0.13 nM, respectively. Real sample analysis was carried out by the standard addition method using the solution extracted from potato chips.