Colorimetric signaling of Cu(II) ions by oxidative coupling of anilines with 4-aminoantipyrine

Abstract

Selective Cu2+ signaling by the oxidative coupling of anilines with 4-aminoantipyrine was investigated. The Cu2+-assisted reaction between N-ethyl-N-(2-hydroxy-3-sulfopropyl)-3,5-dimethylaniline sodium salt and 4-aminoantipyrine resulted in the pronounced color change from colorless to bluish green, with a detection limit of 2.1 x 10(-6) M in 90% aqueous acetonitrile. Furthermore, selective Cu2+ signaling was not affected by the presence of common metal ions as background. The practical utility of this system for the determination of Cu2+ was successfully demonstrated using a convenient chromogenic test strip. (C) 2015 Elsevier Ltd. All rights reserved.