A fluorescent probe for Gallium(III) ions based on 2-hydroxy-1-naphthaldehyde and L-serine

A simple fluorescence probe for Ga(3+ )has been designed and prepared by Schiff base reaction between 2-hydroxy-1-naphthaldehyde and L-serine. This probe has been confirmed to effectively monitor Ga3+ with high specificity over other metal ions and common anions according to the fluorescence change. The mass spectra (ESI-MS) and Job's plot proved evidences of the complex formation with a 1:1 stoichiometry between the probe and Ga3+. The association constant (K) and limit of detection (LOD) were calculated as 7.63 x 10(3) M-1 and 0.11 mu M, respectively. Furthermore, combined with the density functional theory (DFT) calculation and the fluorescence lifetime change, the detection mechanism of the probe to Ga3+ was proposed. The suppression of the photo-induced electron transfer (PET) process and the excited-state intramolecular proton transfer (ESIPT) process is responsible for the fluorescence enhancement of this probe. Additionally, the probe showed good cell permeability and could be also capable of detecting Ga3+ in living cells.