Fluorescence and colorimetric dual-signal sensing of resveratrol and ascorbic acid based on NaYF₄:Yb,Er@NaYF₄...

A novel dual-signal sensing platform is developed for the simultaneous quantitative determination of resveratrol (Res) and ascorbic acid (AA), integrating fluorescence-based quantification with colorimetric visual recognition, with a sensing mechanism based on the inner filter effect (IFE) of a composite system consisting of upconversion nanoparticles (UCNPs), 3,3',5,5'-tetramethylbenzidine (TMB), and ferric ions (Fe³⁺). In this system, Fe³⁺ first oxidizes colorless TMB to blue oxidized TMB (oxTMB), and the formed oxTMB further quenches the fluorescence of the UCNPs through the IFE. When Res or AA is introduced into the system, oxTMB is reduced back to colorless TMB, which results in the fading of the blue solution and the recovery of UCNP fluorescence, thus achieving the dual-signal detection of the two analytes through fluorescence-based quantification and colorimetric qualitative determination. Furthermore, 4-hydroxy-TEMPO is introduced as an AA-specific scavenger, which can effectively eliminate the interference of AA and achieve selective discrimination between Res and AA. This developed sensing platform integrates the prominent merits of simple operation, high sensitivity, excellent specificity, and visual readout. It provides not only a novel analytical strategy for the efficient detection of Res and AA but also broad application prospects in the field of analytical chemistry.