A new coumarin derivative as a highly selective ‘turn-on’ fluorescence probe for La3+ (lanthanum ion) in living zebrafish

In this study, we reported the construction of a new turn-on fluorescent probe NCH based on coumarin for La3+ (lanthanum ion) detection in the environment and biological systems. The fluorescence spectral data demonstrated that the probe NCH has high selectivity, fast response time (50 s), and relatively low detection limit (1.67 μM) for La3+. Moreover, after adding La3+, the fluorescent intensity at 520 nm of NCH was observed to increase by a factor of twelve, accompanied by a significant Stokes shift of 200 nm. In addition, the probe NCH could perform consistently in the pH range (4–10), which created good conditions for the detection of La3+ ions in living organisms. The successful application of NCH in zebrafish embryos indicates that this probe is a dependable tool for monitoring La3+ in biological systems.