Dual-Excitation Ratiometric Fluorescent Probe for Identification of Biogenic Amines and Its Application in Food Spoilage Detection.

The freshness of food is directly connected with safety, hygiene, and human health. Accurate quantification of biogenic amine level is crucial for assessing the food quality. Therefore, a dual-excitation ratiometric fluorescent probe MCCN based on hemicyanine dye for the examination of biogenic amines was constructed. After the addition of biogenic amines to the MCCN solution, an elimination reaction occurred after a nucleophilic addition reaction to form Schiff base MC-CA, resulting in colorimetric and ratiometric fluorescence responses. The probe MCCN solution was blue. After successively adding biogenic amines (cadaverine, n-butylamine and spermidine), the fluorescence emission intensity of probe MCCN at 709 nm reduced under excitation at 650 nm, meanwhile a new fluorescence emission peak emerged at 545 nm gradually increased under excitation at 450 nm, accompanying by a visible color variation from blue to yellow. The probe MCCN also displayed remarkable selectivity toward biogenic amines over other analytes. Based on the above excellent characteristics, the probe MCCN was successfully utilized to detect biogenic amines in the extract supernatant of shrimp and fish during the spoilage process. In addition, photographing the MCCN-loaded food extract supernatant enabled the correlation of color parameters with storage time, affording an accurate and simple method to reveal food spoilage process. The excellent sensing performance makes the MCCN probe a convenient and accurate screening platform for real-time assessing food freshness.