Multiphase detection of crucial biological amines using a 2,4,6-tristyrylpyrylium dye

The strong electrophilicity of arylpyrylium salts was recognized for the colorimetric detection of vital amine analytes, limited to ammonia or methylamines and putrescine as biogenic amine. This report presents conformationally twisted, electrophilic triphenylamine-linked 2,4,6-tristyrylpyrylium salt PyTPA as a single dye to sense various aliphatic/aromatic biogenic amines, nicotine, and guanidine rapidly in nanomolar concentrations. This unexplored styrylpyrylium design offers specific electronic conjugations, steric/geometric constraints with hydrophobicity, and decent thermal/photostability, facilitating precise diverse amines detection in unique fashions. The deep-violet solution/solid dye responded remarkably at 298 K with quick decoloration against putrescine, cadaverine, spermidine, spermine, histamines, serotonin, and 2-phenylethylamine. Further, this dye could detect nicotine at 313 K and guanidine at 298 K distinctively with diminished absorption and unexpected red-shifted emission enhancement. Variation in mechanistic path is recognized in detecting amines holding mono/di-NH₂ groups and short/ long alkane chains, elucidated by mass, ¹H-NMR, FT-IR, SEM, PXRD, and XPS studies. The notable detection of these biogenic amines in different phases is employed for onsite applications to detect fresh chicken and tuna. Nicotine in natural tobacco leaves was identified. Such pyrylium salt provides promising advancements in this class of molecules in detecting diverse biologically significant amines.