A benzyl carbazate-based colorimetric chemosensor for relay detection of Cu2+ and S2- in near-perfect aqueous media

A benzyl carbazate-based colorimetric chemosensor HB (benzyl (E)-2-(2-hydroxy-3-methoxy-5-nitrobenzylidene)hydrazine-1-carboxylate) was synthesized and used for relay detection of Cu2+ and S-2(-). HB can sense Cu2+ by the color variation from yellow to colorless and be used in real sample. HB-Cu2+ detected S2- though demetallation with color variation form colorless to yellow. Detection limits of HB for Cu2+ and S2- were calculated to be 0.20 and 0.60 mu M which are greatly below WHO guidelines (31.4 and 14.8 mu M). In addition, HB and HB-Cu2+ could detect Cu2+ and S-2(-), respectively, without any interference of other ions. The detection processes of HB to Cu2+ and S2- were illustrated by ESI-MS, UV-visible spectroscopy and DFT calculation. (C) 2021 Elsevier B.V. All rights reserved.