Cinnamaldehyde-Based Chemosensor for Colorimetric Detection of Cu ²⁺ and Hg ²⁺ in a Near-Perfect Aqueous Solution

A cinnamaldehyde-based colorimetric chemosensor TAA (N′-((1E,2Z)-3-(4-(dimethylamino)phenyl)allylidene)thiophene-2-carbohydrazide) was newly developed. TAA can detect Cu ²⁺ and Hg ²⁺ ions by different color changes from pale yellow to deep yellow and orange, respectively, in aqueous media. TAA differently binds to Cu ²⁺ as a 1:1 ratio and Hg ²⁺ as a 2:1 ratio. The detection limits towards both analytes turned out to be 0.08 μM for Cu ²⁺ and 0.01 μM for Hg ²⁺ . Moreover, TAA could successfully quantify Cu ²⁺ and Hg ²⁺ in tap and drinking water. The detection processes of TAA towards Cu ²⁺ and Hg ²⁺ were demonstrated by using DFT calculations.