Fluorescent sensing of biogenic amines based on in-situ pre-modification technique and its application for...

Biogenic amines (BAs) as critical biomarkers for freshness evaluation, strongly correlate with microbial spoilage in high-protein foods, which rapid detection is essential for food safety. Selective sensing of aliphatic diamines, such as putrescine (PUT) and cadaverine (CAD), presents challenges due to their lack of functional groups and interference by pH and amino analogs. This work developed a fluorescent sensing method of BAs using perylene derivative PDI-BTMA and in situ pre-modification technique in aqueous media. The PDI-BTMA interacted with PUT/CAD pre-modified by o-phthalaldehyde and mercaptopropionic acid forming supramolecular aggregates, inducing fluorescence quenching. The method achieved linear detection of 0.1-50 μM with limit of detection of 55.6 nM (PUT) and 36.3 nM (CAD). Freshness evaluation was demonstrated by quantifying PUT/CAD changes in stored hairtail. As the first fluorescent method combining in-situ pre-modification to specifically detect PUT and CAD, this work provides a novel paradigm for direct detection of small molecules with simple structure.