Rapid, Selective, and Sensitive Detection of Silver Ions Using Thiourea‐Based Schiff Base as Colorimetric Chemosensor

ABSTRACT A colorimetric probe, ( E )‐1‐(3,4‐dimethoxybenzylidene)thiourea (MBT‐SB), has been synthesized as well as characterized by IR, 1 H NMR, 13 C NMR, and LC‐MS. The elevation in absorbance as well as a change in the color of MBT‐SB in 1:9 DMF‐water ( v/v ) solution in the presence of only Ag + signifies a selective and sensitive detection using the spectrophotometric method even in the vicinity of other cations also (Cd 2+ , Ca 2+ , Co 2+ , Fe 2+ , Pb 2+ , Ni 2+ , K + , Cu 2+ , Na + , Ba 2+ , NH 4 + , Al 3+ , Hg 2+ , Mg 2+ , Mn 2+ , and Ag + ). The binding stoichiometry of the probe with the metal ion Ag + has been examined by Job's plot. The synthesized probe shows an extremely low detection limit of 0.006720 ppm. The interaction of the target metal ion with MBT‐SB was studied and discussed on the basis of sensing behavior, coexisting effect, and DFT calculations. The present analytical method has been successfully used for the quantitative determination of Ag + in tap water.