A Novel Coumarin-Based Fluorescent Probe for Sequential Detection of Al3+ and H2PO4-

A coumarin-derived acylhydrazone probe (L) was designed and synthesized for successive detection of Al3+ and H2PO4- in DMSO/H2O solution. The probe L exhibited high selectivity towards Al3+ with visible color change and prominent fluorescence enhancement at 592 nm, while the in situ prepared L-Al3+ complex could selectively recognize of H2PO4- via fluorescence quenching. The detection limits for Al3+ and H2PO4- were calculated to be 3.4 and 11.0 nM, respectively. The binding ratio of L to Al3+ was obtained as 2 : 1 according to the Job's plot and ESI-MS while the association constant was determined to be 2.13x10(4) M-1. Furthermore, the probe L was successfully applied in detection of Al3+ and H2PO4- with test strips and in real water samples.