Introducing a nanozyme-based sensor for selective and sensitive detection of mercury(II) using its inhibiting effect on production of an indamine polymer through a stable n-electron irreversible system

A sensitive and selective nanozyme-based sensor for Hg2+ detection has been constructed by utilizing a stable n-electron irreversible system using 3,3 '-diaminobenzidine (DAB) for producing an indamine polymer as the analytical probe. In this system, oxidation of DAB to indamine polymer by hydrogen peroxide was catalyzed using gold nanozyme. In the presence of Hg2+, production of the indamine polymer was inhibited and consequently the corresponding change in absorbance measured at 460 nm was linearly related to the concentration of Hg2+. The method showed good selectivity toward Hg2+ against its coexisting species and a linear working range of 0.14-7.35 mg L-1 with a detection limit of 20 mu g L-1 was achieved for Hg2+ measurement. The method is appropriate for the analysis of Hg2+ in water samples. [GRAPHICS] .