Manganese cobalt-MOF@carbon nanofiber-based non-enzymatic histamine sensor for the determination of food freshness

Early detection of histamine in foodstuffs/beverages could be useful in preventing various diseases. In this work, we have prepared a free-standing hybrid mat based on manganese cobalt (2-methylimodazole)-metal organic frameworks (Mn-Co(2-MeIm)MOF) and carbon nanofibers (CNFs) and explored as a non-enzymatic electrochemical sensor for determining the freshness of fish and bananas based on histamine estimation. As-developed hybrid mat possesses high porosity with a large specific surface area and excellent hydrophilicity those allow easy access of analyte molecules to the redox-active metal sites of MOF. Furthermore, the multiple functional groups of the MOF matrix can act as active adsorption sites for catalysis. The Mn-Co(2-MeIm)MOF@CNF mat-modified GC electrode demonstrated excellent electrocatalytic activities toward the oxidation of histamine under acidic conditions (pH = 5.0) with a faster electron transfer kinetics and superior fouling resistance. The Co(2-MeIm)MOF@CNF/GCE sensor exhibited a wide linear range from 10 to 1500 mu M with a low limit of detection (LOD) of 89.6 nM and a high sensitivity of 107.3 mu A mM(-1) cm(-2). Importantly, as-developed Nb(BTC)MOF@CNF/GCE sensor is enabled to detect histamine in fish and banana samples stored for different periods of time, which thus indicates its practical viability as analytical histamine detector.