Naked-eye detection of Cys using simple molecular systems of curcumin and Hg2+

Abstract

A sensing ensemble for cysteine was assembled conveniently by simply mixing curcumin (Cur) and Hg²⁺ in buffered acetonitrile/HEPES (10 mM, 7/3, v/v, pH 7.4) solutions. In the ensemble, Hg²⁺ serves as the receptor, and Cur functions as the indicator in sensing the analyte. The detection can be performed either spectroscopically, by the decrease of the UV-Vis absorbance at 430 nm and the increase of the UV-Vis absorbance at 355 nm, or visually by the color change from colorless to yellow upon addition of an aqueous solution of the analyte to the solution of the ensemble.