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.

A review on chemical and electrochemical methodologies for the sensing of biogenic amines.

Biogenic amines (BA) are biomolecules of low molecular weight with organic basic functionalities (amine group) that are formed by the microbial decarboxylation of amino acids of fermented food/beverages. Hence BAs are an important indicator in estimating the freshness and quality of meat, seafood, and industrial food products with high protein content. The reaction of BAs with nitrites available in certain meat products forms nitrosoamine, a carcinogenic compound. Hence BAs are in general considered to be a food hazard and monitoring the level of BAs in food samples becomes crucial as their high concentrations may lead to health problems. This review offers an overview of the available chemical and electrochemical methods that are typically used for the sensing of BAs in food samples. Certain compounds are known to selectively interact with BAs via chemical or non-covalent interactions and these interactions are often accompanied by fluorescence or visible color changes (sometimes visual detection) that could be monitored/assessed using a fluorescence spectrophotometer or UV-vis spectrophotometer (colorimetric methods). The colorimetric methods are limited by sensitivity and selectivity as they are based on straight-forward chemical reactions. In the case of electrochemical sensing of BAs, mediators are often used which undergo oxidation/reduction to produce intermediates that could interact with BAs accompanied by changes in their electrochemical potential. Overall, this review summarizes the available chemical and electrochemical strategies towards the sensing of BAs with a discussion on further prospects.