A specific electrochemiluminescence sensor for selective and ultra-sensitive mercury(ii) detection based on dithiothreitol functionalized copper nanocluster/carbon nitride nanocomposites

Abstract

Electrochemiluminescence (ECL) sensors are useful for the detection of heavy metal pollutants, in particular mercury(II) ions, in water samples. We demonstrate the superior sensing performance of Hg²⁺ using a nanocomposite material based on carbon nitride nanosheets (CNNSs) and copper nanoclusters functionalized by dithiothreitol, which not only stabilizes the clusters, but also improves the sensitivity of Hg²⁺ detection. The ECL mechanism is related to the reaction of the nanocomposite with K₂S₂O₈ in the electrochemical system, while the presence of Hg²⁺ leads to quenching of its excited state, and the suppression of the formation of anion-radicals. The Hg(II) sensor presented here is cheap and fast, and shows high selectivity for the detection of Hg²⁺ on the background of other mono-, di-, and trivalent ions, with a linear range of 0.5–10 nM and the detection limit as low as 0.01 nM.