Highly selective colorimetric schiff base chemosensor for detection of Cu²⁺

Abstract

A highly selective colorimetric chemosensor for Cu²⁺ has been designed using a novel Schiff base based on 2-hydroxy-1-naphthaldehyde. On addition of Cu²⁺, the color of Schiff base solution changes from yellow to colorless, which can be viewed with the naked eye. The proposed chemosensor is sensitive to Cu²⁺ with the detection limit of 1.3×10^-7 mol L^-1. The mechanism of the colorimetric chemosensor for the detection of Cu²⁺ has been investigated in detail through UV-vis, Job plot, ¹H NMR and FT-IR data. The results show that a stoichiometric complex (1:1) is formed between Schiff base and Cu²⁺, based on the molecular proton transfer process. The selectively of the chemosensor for detection of Cu²⁺ over common cations has been investigated by UV-vis spectroscopy. The test strip for Cu²⁺ prepared according to the principle of colorimetric chemosensor illustrates the advantages of this method in terms of convenience and effectiveness.