Novel fluorescent sensor with 2,5-furandicarboxylic acid as the ligand for histamine detection

Using effective and sustainable technologies for food quality evaluation has become imperative due to the growing concerns regarding food safety and security. Fluorescent-based sensing is a rapid monitoring technique for food spoilage detection; however, the technique employs fossil-based compounds for sensor development. Here, a fluorescent sensor for histamine (biogenic amine) as an indicator for the detection of spoilage in the fish matrix was fabricated using 2,5-furandicarboxylic acid (FDCA) as the organic ligand. FDCA is a biobased molecule and serves as a replacement for petroleum-derived terephthalic acid, which is widely used in the synthesis of fluorescent metal-organic frameworks (MOF). Herein we report a MOF that was synthesized using two organic ligands: FDCA and adenine with Fe as the metal center, denoted as Fe-AD-FDCA. The fluorescent sensor was created by covalently bonding methyl red (MR) with an NH2-rich Fe-AD-FDCA framework by post-synthetic modification. When exposed to histamine, the sensor showed a fluorescent emissive response that increased MR emission and produced a distinctly visible color shift from dull pink to blue. By spreading and solidifying MR@Fe-AD-FDCA in the water-phase sodium salt of carboxy methyl cellulose (CMC-Na), portable sensory hydrogels were produced. This fluorescence sensor's ability could be utilized for real-time monitoring of the freshness of raw fish samples.