Fluorescent sensor-modified polyvinyl alcohol films for the detection of amine vapor based on PET (photo-induced electron transfer)

Biogenic volatile amine vapors are released during food spoilage. In this work, we investigated the fluorescent sensing properties of an intramolecular photo-induced electron transfer (intraPET)-type fluorescent sensor, TF-2, composed of anthracene-AminoMeCNPhenylB(OH)₂, for amine. TF-2 solutions in the absence of amines show strong fluorescence emission due to the formation of intraPET inactive (fluorescent) species with the intramolecular OH⋯N hydrogen bonding between the nitrogen atom of the amino moiety and the hydroxyl group of the B(OH)₂ moiety. Moreover the TF-2 solutions caused a decrease in the fluorescence intensity upon the addition of amines, which is attributed to the intermolecular PET (interPET) from the amine to TF-2. Moreover, we prepared a TF-2-modified polyvinyl alcohol (PVA) film for detecting volatile amines. It was found that the TF-2-modified PVA film upon exposure to amine vapors shows a drastic decrease in the fluorescence intensity due to the interPET from the amine to the TF-2. Finally, we monitored changes in the fluorescence emission of the TF-2-modified PVA film upon exposure to volatile amine vapors released from the decomposing matter during the spoilage of raw shrimp. Here, we propose that the PET-type fluorescent sensor based on a fluorescence quenching (turn-off) system is one of the most promising and useful functional dye materials for detecting organic amines.