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

A novel fluorescent sensor based on coumarin was developed for the sequential detection of Al3+ and F− ions in ethanol, exhibiting a large Stokes shift of 190 nm. The probe displayed “off‐on‐off” responses towards Al3+ 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 Al3+ was elucidated using Job‘s plot, 1H NMR, optical titrations, and ESI‐MS. Additionally, the probe demonstrated an AIE property in DMSO/H2O solutions. Its successful application in measuring Al3+ 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. A novel coumarin‐based fluorescent probe for sequential detection of Al3+ and F− was developed. The probe showed high sensitivity and selectivity to Al3+ and F− in ethanol at red region (630 nm) with detection limits of 2.48×10−8 M and 2.34×10−8 M, respectively. Meanwhile, L showed an AIE property in DMSO/H2O solutions. Moreover, the probe could be effectively applied in detection of F− in toothpastes by “naked eye” and detection of Al3+ and F− in real water samples.