Hybrid polymer dots with isothiocyanate functional groups for rapid sensing tyramine in aquatic products

Biogenic amines are critical indicators for the quality and safety of aquatic products, and biogenic amine poisoning could threaten human health. Therefore, it is crucial to develop easily operated and efficient analytical sensors for strict tyramine detection. To address this need, ratiometric fluorescent sensors have been developed for the detection of tyramine. F8BT-RBI polymer dots and PVK-FITC polymer dots were prepared by the semiconductor polymers Poly [(9, 9-di-n-octylfluorenyl-2, 7-diyl)-alt-(benzo [2,1,3] thiadia-zol-4, 8-diyl)] (F8BT) and Poly (9-vinylcarbazole) (PVK), combined with rhodamine B isothiocyanate (RBI) and fluorescein isothiocyanate (FITC) through reprecipitation methods. The ratiometric fluorescent sensors rely on the changes in fluorescence intensity in dual channels caused by the intramolecular charge transfer (ICT) resulting from the reaction between isothiocyanate dyes and tyramine. This approach enables accurate detection of tyramine content within specific linear ranges. For instance, PF8BT-RBI covers a range of 2.74–20.6 mg L −1 with a limit of detection (LOD) of 0.14 mg L −1 , while PPVK-FITC covers 20.6–61.7 mg L −1 with an LOD of 0.59 mg L −1 . PF8BT-RBI and PPVK-FITC had potential for fluorescence detection of tyramine, and were applied in the detection of tyramine in aquaculture water and tuna. By utilizing Pdots and isothiocyanate dyes, these sensors can meet the demand for ensuring the freshness and safety of aquatic products.