A Schiff-base derived colorimetric sensor with high performance for the detection of copper and cyanide ions and its real time application.

A Schiff-base derived chromogenic probe 2-amino-3-((E)-4-hydroxy-3,5-dimethoxybenzylidene amino)maleonitrile (SYDA) has been synthesised successfully. Nuclear Magnetic Resonance (NMR) and High-Resolution Mass Spectrometry (HRMS) spectral analyses have been employed to characterise the synthesised sensing probe SYDA. The limit of detection for Cu2+ and CN- was found to be 19.2 nM and 94.5 nM, respectively, and the reaction time was less than 10 seconds. The interaction of the sensing probe with Cu2+ and CN- resulted in a significant colour change from colourless to pale yellow and yellow respectively. The colorimetric detection of Cu2+ and CN- was demonstrated using bottle images and paper strips. Further, the recognition of Cu2+ and CN- in the solid state, environmental water samples, and swab test kits were achieved.