A phthalazine-based two-in-one chromogenic receptor for detecting Co(2+) and Cu(2+) in an aqueous environment

A new multifunctional and highly selective chemosensor for Co(2+) and Cu(2+) was designed and synthesized. could simultaneously detect both Co(2+) and Cu(2+) by changing its color from pale yellow to pink and to orange in a near-perfect aqueous solution. The binding modes of to Co(2+) and Cu(2+) were determined to be a 2 : 1 complexation stoichiometry through Job's plot, ESI-mass spectrometry analysis and (1)H NMR titration. The detection limits (1.5 and 2.1 μM) of for Co(2+) and Cu(2+) were lower than the DEP guidelines (1.7 μM for Co(2+)) and the WHO guidelines (31.5 μM for Cu(2+)) for drinking water. The chemosensor could be used to quantify Co(2+) and Cu(2+) in water samples. Moreover, could be used as a practical, visible colorimetric test kit for both Co(2+) and Cu(2+). The sensing mechanisms of Co(2+) and Cu(2+) by were supported by theoretical calculations.