Bidirectional rapid sensing based on rare-earth upconversion nanoparticles for the ascorbic acid and hydrogen peroxide detection

The current detection methods for L-Ascorbic Acid (AA) and hydrogen peroxide (H 2 O 2 ) often face limitations in sensitivity, rapidity, and practical application. Addressing these challenges, this study introduces a bidirectional rapid sensing platform based on rare-earth upconversion nanoparticles (UCNPs) for the detection of AA and H 2 O 2 . The developed probe, combining Tm-doped NaYF 4 UCNPs with an iron chelate (SA-Fe III ), leverages the inner filtration effect for efficient detection. By employing both fluorescence and colorimetric methods, the proposed system achieves linear detection ranges of 0–100 μM for AA and 0–71.7 μM for H 2 O 2 , with detection limits as low as 0.1 μM and 0.45 μM, respectively. Furthermore, a smartphone-based image analysis technique demonstrates the potential for rapid, on-site concentration measurements. This work significantly enhances the practicality of AA and H 2 O 2 detection, offering a sensitive, fast, and user-friendly approach that holds promise for applications in clinical diagnostics, food safety, and agricultural stress monitoring.