Tetranitrile-anthracene as a probe for fluorescence detection of viscosity in fluid drinks via aggregation-induced emission

Viscosity is an important quality parameter for fluid drinks, which can serve as an indicator for the extent of food spoilage, since the viscosity of fluid drinks varies during the spoilage process. In this study, a near-infrared fluorophore based on tetranitrile-anthracene (TPAEQ) was designed for viscosity determination via aggregation-induced emission (AIE). With increased viscosity, TPAEQ showed enhanced emission at around 759 nm with a large Stokes shift of 195 nm in water. The probe TPAEQ was successfully used to monitor the viscosity changes during the food spoilage process for fluid drinks. Moreover, the probe TPAEQ has effectively been utilized to determine the mass concentrations of food thickeners added in the real fruit drinks. The approach for the viscosity determination could enable the on-site direct detection with convenient operation in food safety inspection applications.