Naturally Occurring Flavonol, Quercetagetin 5,6,7,3′,4′-Pentamethyl Ether (Marionol), as a Nontoxic Plant-Based Fluorescent Probe for Rapid, Sensitive, and Selective Detection of Cu²⁺ in Water

Abstract

Herein, we report a naturally occurring flavonol, quercetagetin 5,6,7,3′,4′pentamethyl ether (known as marionol), as a nontoxic fluorescent probe for rapid, sensitive, and selective detection of Cu 2+ in water. The interaction between marionol and Cu 2+ ions is studied by various state-of-the-art spectroscopic techniques such as 1 H NMR, UV−vis, fluorescence, and high-resolution mass spectrometry (HRMS). Marionol shows strong fluorescence quenching in the presence of Cu 2+ , whereas other interfering cations such as