A pyrylium salt-based fluorescent probe for the highly sensitive detection of methylamine vapour.

The amine vapour produced by microorganisms is an important indicator of food spoilage. Amines are also ubiquitous in the chemical industry. The development of molecule-based ion sensors has been a pivotal issue that is currently receiving considerable attention. In this work, a new pyrylium salt-based fluorescent probe MTPY has been developed as a rapid, highly sensitive, and selective sensor for methylamine vapour. MTPY exhibits an obvious fluorescence response from yellow to cyan towards CH 3 NH 2 vapour. The calibration curve of titration analysis shows a linear relationship of the fluorescence intensity at 514 nm versus the methylamine concentration in the range of 0.1-2 ppm. In addition to the linearity ( R 2 = 0.974) and short response time with a low detection limit (2.6 ppt, 8.4 × 10 -8 M), the sensing mechanism was traced using mass spectrometry.