One-pot synthesis of lanthanide-doped silica film as a ratiometric fluorescent probe for selective amine vapours detection

In this work, the development of a novel paper-supported ratiometric fluorescent sensing platform for amines detection and discrimination based on co-doped Tb3+ and Eu3+ silica film is reported. The sensor film was obtained by the sol-gel process, in a one-pot straightforward synthesis approach. After exposure to different amines, the resulting intensity ratio between Tb3+ and Eu3+ emission bands presents characteristic values that can be ascribed to the different amines. The higher emission intensity ratios were found for amines with the higher pKa values, as in the case of biogenic amines. The sensor can be stored for more than 120 days, keeping the capacity to detect and distinguish different amines. The prepared fluorescent probe was tested as a food freshness indicator in beef and tuna samples, where notable changes were observed during the food degradation. This proof-of-concept shows the capability of the developed sensor platform to be applied in the detection of multiple amines, and in daily and quality control operations by “naked-eye” inspection.