Tetrakis(4-pyridylphenyl)ethylene-decorated metal-organic frameworks with aggregation-induced chemiluminescence emission on paper-based platform for volatile sulfur compounds measurement.

Volatile sulfur compounds (VSCs) in human exhaled breath (EB) are considered as biomarkers of halitosis. Convenient and reliable detection of VSCs has significance for confirming oral health. Herein, copper-based metal-organic framework (Cu-TPPE) was synthesized by utilizing aggregation-induced emission (AIE) phenomenon of tetrakis(4-pyridylphenyl)ethylene (TPPE) ligand on paper. Due to electron transfer between Cu2+ and TPPE, the aggregation-induced emission of TPPE was quenched. In the presence of VSCs, the affinity between S and Cu led to delocalization of Cu in Cu-TPPE, thus recovering the aggregation-induced chemiluminescence emission between TPPE and bis(2,4,6-trichlorophenyl)oxalate (TCPO)-H2O2. Based on this principle, selective and sensitive determination of VSCs in human EB was achieved. The linear range of quantification of H2S was 0.07-8.0 ppm, and the detection limit was 0.03 ppm. This paper-based chemiluminescence platform has been applied to the detection of VSCs in real breath samples.