Sequential detecting of Ni2+ and CN− with a Chalcone-based colorimetric chemosensor in near-perfect water

Abstract

As a chalcone-based colorimetric chemosensor for consecutive detection of Ni2+ and CN−, HNP ((E)-3-(2-hydroxy-5-nitrophenyl)-1-(pyridin-2-yl)prop-2-en-1-one) was developed. HNP detected exclusively Ni2+ through the variation of color from yellow to orange. The detection limit of HNP for Ni2+ was calculated to be 0.209 μM. In the competition experiment, HNP was not considerably disturbed by various metals in the sensing of Ni2+. Moreover, the HNP-Ni2+ complex showed a selective color variation from orange to yellow for CN−. The detection limit of the HNP-Ni2+ complex for CN− was calculated to be 20.8 μM. In the interference test for CN−, HNP-Ni2+ complex was not significantly inhibited by other anions for detecting CN−. In water samples, the detecting ability of HNP for Ni2+ and CN− was satisfactorily performed. The binding ratios of HNP to Ni2+ and HNP-Ni2+ complex to CN− were determined as a 1:1 with Job plot and ESI-mass. Binding mechanisms of HNP to Ni2+ and HNP-Ni2+ to CN− were demonstrated by ESI-MS, Job plot, UV–vis, FT-IR analysis, and DFT calculations.