A Novel Red Fluorescent Probe for the “Off‐On‐Off” Detection of Al3+ and F− in Samples of Drinking Water and Toothpaste

Abstract A novel fluorescent sensor based on coumarin was developed for the sequential detection of Al 3+ and F − ions in ethanol, exhibiting a large Stokes shift of 190 nm. The probe displayed “off‐on‐off” responses towards Al 3+ and F − at the red region of 630 nm, with detection limits of 2.48×10 −8 M and 2.34×10 −8 M, respectively. The binding mechanism between the probe and Al 3+ was elucidated using Job‘s plot, 1 H NMR, optical titrations, and ESI‐MS. Additionally, the probe demonstrated an AIE property in DMSO/H 2 O solutions. Its successful application in measuring Al 3+ and F − in water samples was observed. Moreover, with the convenience of “naked eye” detection, the probe could be effectively utilized for identifying F − in toothpastes.