A highly sensitive and selective chemosensor for Pb²⁺ based on quinoline–coumarin

Abstract

In this study, a highly sensitive and selective fluorescent chemosensor, ethyl(<i>E</i>)-2-((2-((2-(7-(diethylamino)-2-oxo-2<i>H</i>-chromene-3-carbonyl)hydrazono)methyl)quinolin-8-yl)oxy)acetate (1), was synthesized and characterized by ¹H NMR, ¹³C NMR and ESI-MS. Sensor 1 showed an "on-off" fluorescence response to Pb²⁺ with a 1 : 1 binding stoichiometry in CH₃CN/HEPES buffer medium (9 : 1 v/v). The detection limit of sensor 1 to Pb²⁺ was determined to be 0.5 μM, and the stable pH range for Pb²⁺ detection was from 4 to 8.