Solvent-dependent selective fluorescence assay of aluminum and gallium ions using julolidine-based probe

Abstract The selective assay of aluminum and gallium ions is reported using fluorescence enhancement of a julolidine-based probe (PJI) in aqueous and nonaqueous solvents. The binding properties of PJI with metal ions were investigated by UV–vis, fluorescence, and electrospray ionization mass spectrometry. PJI gave no fluorescence in water, dimethylformamide, and methanol. The addition of aluminum ions switches on the fluorescence of the sensor PJI in both buffer and dimethylformamide, while other metal ions show no significant fluorescence changes. However, in methanol, its fluorescence can be selectively turned from a turn-on fluorescent sensor for gallium ions. The complex stability constants ( K a ) for the respective stoichiometric 1:1 complexation of PJI with aluminium and gallium ions were obtained by fluorimetric titrations.