Bodipy-based Ratiometric Fluorescent Probe for Sensing Fe³⁺ with Large Absorption and Emission Shifts

Secondary development of fluorescent probes can fully exploit the optical advantages of existing probes while avoiding resource wastage from redundant research and development. This paper investigates the metal ion recognition properties of a reported probe (BDF) in methanol solution. Upon addition of Fe³⁺, the probe solution exhibits a distinct color change from light blue to pale pink, accompanied by a 55nm blue shift in the maximum absorption wavelength. Concurrently, the fluorescence emission shifts from red to bright green, with a 155nm blue shift in the emission wavelength. Both signals feature large Stokes shifts, significantly enhancing the clarity and accuracy of colorimetric recognition. The calculated UV-Vis and fluorescence limits of detection (LOD) were 0.0984 µM and 1.3309 µM, respectively, with limits of quantification (LOQ) of 0.32 µM and 4.43 µM. To validate its practical utility, test strips, medical swabs, and a smartphone for quantitative Fe³⁺ detection were employed, significantly enhancing the probe's potential and convenience for real-world applications.