A new Schiff base fluorescent indicator for the detection of Mg2+ and its application to real samples

A new Schiff base fluorescence probe, 3-Allylsalicylaldehyde salicylhydrazone (L), for Mg 2+ was designed and synthesized. The fluorescence of the sensor L was enhanced remarkably by Mg 2+ with 2:1 binding ratio, and the binding constant was determined to be 1.02 × 10 7  M −1 . Probe L had high sensitivity for Mg 2+ in a solution of DMF/water (4:1, v/v, pH 7.5), and the detection limit was 4.88 × 10 −8  mol/L. Common coexistent metal ions, such as K + , Na + , Ag + , Ca 2+ , Zn 2+ , Ba 2+ , Bi 2+ , Cu 2+ , Ni 2+ , Hg 2+ , Fe 3+ , and Al 3+ , showed little or no interference on the detection of Mg 2+ in solution. The fluorescence probe L, which was successfully used for the determination of trace Mg(II) in real samples, was shown to be promising for liquid-phase extraction coupled with fluorescence spectra.