A novel spectroscopic probe for detecting food preservative NO2-: Citric acid functionalized metal-organic framework and luminescence sensing

A functionalized MOF-based hybrid material (UiO-66-NH2-Cit) is synthesized based on the covalent attachment of UiO-66-NH2 with citric acid (Cit) through a condensation reaction between them. The transformation of the amino groups is validated by FTIR and PXRD, etc. UiO-66-NH2-Cit is further developed as a luminescent probe to detect NO2- (one kind of food preservative). The results show that it has selectivity and sensitivity in photo response to nitrite comparing with other preservatives. The sensing mechanism is also discussed.