A highly selective fluorescent ‘turn-on’ chemosensor for Hg2+ based on a phthalazin-hydrazone derivative and its application in human cervical cancer cell imaging

A new phthalazin-hydrazone based fluorescent chemosensor (E)-5-(diethylamino)-2-((2-(phthalazin-1-yl)hydrazono)methyl)phenol (1) was reported. Sensor 1 showed a high selectivity and sensitivity towards Hg2+ by giving significant fluorescence enhancement at 550 nm over other tested cations in DMSO/H2O (80 : 20, v/v) medium. The association constant was 1.0 × 104 M−1 between sensor 1 and Hg2+. Sensor 1 showed a nanomolar detection limit of 26.1 nM Hg2+. Finally, the fluorescence imaging experiments for the detection of intracellular Hg2+ in human cervical cancer HeLa cells showed its practical utility in biological samples.