Amine‐Responsive Ratiometric Nanofibre Film Based on FITC/Eu Complex for Real‐Time Visual Monitoring of Shrimp Freshness

Developing simple and reliable sensors for food freshness is a key goal in intelligent packaging. In this study, a ratiometric fluorescent nanofibre film was successfully developed for real‐time visual monitoring of shrimp freshness. The film was constructed by embedding an amine‐responsive fluorophore, fluorescein isothiocyanate (FITC) and a stable reference fluorophore, Eu (DBM) 3 Bpy, into an electrospun polyvinyl alcohol (PVA) matrix. The sensing principle relies on the pH‐driven enhancement of FITC's green emission (530 nm) in the presence of biogenic amines, whereas the Eu‐complex provides a constant red reference signal (610 nm). This dual‐emission system creates a clear fluorescence colour change from orange to yellow‐green as shrimp spoils. The sensor exhibited high selectivity and a rapid response, detecting spoilage within 6 h at 25°C. The maximum colour difference (ΔE) reached 64.78, allowing for unambiguous visual detection. This robust and easy‐to‐fabricate nanofibre film holds great promise for practical applications in food safety and intelligent packaging technology.