Designed Synthesis of Fluorescence 'Turn-on' Dual Sensor for Selective Detection of Al3+ and Zn2+ in Water.

1-(Pyridin-2-yl-hydrazonomethyl)-naphthalen-2-ol (PNOH) is a naphthalene-based fluorescence dual chemo-sensor for Al3+ and Zn2+. The probe (PNOH) is spectroscopically characterised and the chemo-sensing mechanism has been demonstrated through 1H NMR, absorption and both steady state and time resolved fluorescence study. The ‘turn-on’ luminescence property of PNOH is used for the selective detection of trace amount of Al3+and Zn2+via chelation enhanced fluorescence (CHEF) through complex formation. The 1:1 stoichiometry of each sensor-metal complex is observed from Job’s plot based on UV-Vis titration. Most promising advantage of the probe (PNOH) is its application in the one-pot detection of Al3+ (λem- 460 nm) and Zn2+ (λem- 510 nm) exciting at same wavelength (λex- 420 nm) while high intense emission appears at two different wavelengths. Limit of detection (LOD) of PNOH towards Al3+ & Zn2+ are found to be 60 nM & 365 nM respectively. Real water sample analysis has also been demonstrated by using the probe PNOH.