A curcumin derived probe for colorimetric detection of azide ions in water

Abstract

A curcumin based probe (CUC-P) having an active alkyne moiety has been synthesised for selective detection of azide (N₃⁻) ions in aqueous medium. In the presence or absence of Cu(I)/Cu(II) ions, CUC-P visibly changes its colour and fluorescence profile upon addition of N₃⁻ ions, allowing facile discrimination from other common ions. The detection limits for N₃⁻ ions measured using the UV-Vis spectroscopic method and the fluorescence method are 10 μM and 1 μM, respectively. Moreover, the Cu(II) complex of CUC-P shows changes in its colour and emission profile in the presence of N₃⁻ ions more rapidly, making both CUC-P and its Cu(II) complex excellent, highly selective colorimetric probes for N₃⁻ ions. The recognition of N₃⁻ ions may be documented on a paper strip in the solution state and even simply by mechanical grinding in the solid state.