A dual-functional colorimetric and on-off fluorescent probe based on purine derivative for detecting Pd2+ and Cu2+: Application as test strips

A Schiff base-type fluorescent probe, PTAID, based on purine derivative was designed and synthesized. To our delight, this probe PTAID could quickly recognize Pd2+ and Cu2+ in HEPES buffer solution without the interfering from other ions. The fluorescent probe PTAID displayed significant and specific fluorescence quenching towards Pd2+ and Cu2+ with high selectivity and sensitivity, and accompanied by a visual color change of the probe solution from colorless to yellow. The detection limits of PTAID for Pd2+ and Cu2+ in HEPES buffer solution were 0.63 mu M and 1.19 mu M, respectively. Moreover, the binding mechanisms of PTAID towards Pd2+ and Cu2+ were supported by Job's plot. Finally, the probe PTAID was successfully made test paper to detect Pd2+ and Cu2+ in a solid state.