Real time NIR detection of biogenic amine using an Yb4L4 tetrahedron

Fluorescent sensors of biogenic amines (BAs) due to their excitation or emission in the UV-Vis region, which limits its application in the field of bioanalysis. Herein, an Yb(III) tetrahedral Yb4L34 with ILCT characteristic was constructed from a tris-beta-diketone ligand, its spin-coated film shows high sensitivity and fast reversible responses to some BAs with the ppm level detection limit and millisecond response time in NIR region. Compared with Yb4L24, the response time of Yb4L34 was effectively reduced by enlarge the cavity volume and rhombus opening lying on the edges of cage, this indicates that the porosity of film was further enhanced and the interaction time (between Yb4L34 and BAs) was decreased. Moreover, the response time of Yb4L34 was faster than that of most fluorescent amine sensors. In addition, the emission of Yb4L34 in NIR region shows significantly quenching after exposure to the vapor of spoiled fish in 89 ms, which implies that Yb4L34 could be used to real time monitor freshness of food.