An aminoquinoline based fluorescent probe for sequential detection of Znic (II) and inorganic phosphate and application in living cell imaging

Abstract

A novel fluorescent probe 5‐(diethylamino)‐2‐(((2‐(hydroxymethyl)quinolin‐8‐yl)imino)methyl)phenol (QS) was synthesized by condensation reaction of 8‐aminoquinoline derivative and 4‐(diethylamino)salicylaldehyde. It was found that the probe QS was capable of high selectivity and sensitivity about specific color and fluorescence changes towards Zn2+ ion in EtOH‐H2O (v/v = 4/1, 0.01 M, Tris–HCl buffer, pH = 7.30) solution. The interaction of QS with Zn2+ ion illustrated a “turn‐on” fluorescence response at 550 nm (λex: 458 nm), moreover, after the subsequent addition of inorganic phosphate (Pi) into the solution above, a “turn‐off” fluorescence response was observed. The sensing ability of the probe QS towards Zn2+ was confirmed by fluorescence titration, UV–Vis titration and HRMS analysis. Besides, the intracellular sensing behavior of QS with Zn2+ and Pi were captured in living PC12 cells. The limit of detection (LOD) for Zn2+ and Pi sensing was found to be 0.03 μM and 0.08 μM, respectively.