Cu(OH)2 nanowire arrays@Cu Foam for high–sensitivity nonenzymatical electroanalysis of histamine: Exploration of electron transfer kinetics and determination of histamine levels in Lactobacillus sakei subsp. sakei–inoculated fermented mandarin fish

Abstract

Presently, Cu(OH)2 nanowire arrays@Cu Foam (Cu(OH)2–NWA@Cu Foam) nanostructure has been confirmed to possess an excellent capacity of nonenzymatical electroanalysis of histamine (His). Based on Cu(OH)2–NWA@Cu Foam electrode, electrochemical investigations elucidated electron transfer kinetics principles of electrooxidation of His. Substantially, it was realized that a four–electron–transferring dehydrogenation was involved in diffusion–controlled electrooxidation of His, contributing tremendously to establishing as–proposed mechanization of His electrooxidation. At optimal conditions, Cu(OH)2–NWA@Cu Foam electrode reflected excellent electrochemical performance such as sensitivity of 3.089 mA mM–1 cm–2, limit of determination of 94 nM, respond time of 1.6 s and linear respond rang of 0.5–1250 μM. The outperformed electroanalytical performance can be physically explicated by the dedications from larger exposed surface area, bigger interface–hydrophilicity–deduced His diffusion coefficient and less charge transfer resistance. Moreover, the outstanding selectivity, stability and reproducibility of Cu(OH)2–NWA@Cu Foam electrode ensured its practical effectiveness in regulating real His levels in fermented mandarin fish. Compared with control group, the mandarin fish by inoculating Lactobacillus sakei subsp. sakei delivered less His contents, deducing that inoculation of Lactobacillus sakei subsp. sakei can effectively depress His generation during fermentation process. Eventually, the one–step as–established Cu(OH)2–NWA@Cu Foam nanostructure positioned itself as an upcoming possibility to pursue commercialized utilization.