Colorimetric cadmium ion detection in aqueous solutions by newly synthesized Schiff bases.

Two newly synthesized Schiff bases DMCA and DMBA were used for selective detection of Cd over a wide range of other metal ions in acetonitrile (ACN)/ Tris-HCl buffer (10 mM, pH 7.32, v/v 2:1). The sensors can detect Cd ions by colour changes from colourless to orange for DMBA and yellow to reddish for DMCA. Response of the probes towards metal ions was investigated by using UV-vis spectroscopy. The complex stoichiometry between the sensors, DMBA and DMCA, and Cd was found to be 2:1 and the binding constants were calculated to be 2.65 ×10 M and 4.95 ×10 M, respectively. The absorbance-based detection limits of DMBA and DMCA were calculated as 0.438 μM and 0.102 μM, respectively. The sensors were also successfully applied to real samples.