Colorimetric and Highly Selective Fluorescence "Turn‐on" Detection of Cr3+ by Using a Simple Schiff Base Sensor

A simple 8-quinolinecarboxaldehyde derived antipyrine Schiff base (QA) was synthesized and characterized, which exhibited high selectivity to Cr3+ over other metal cations. The Cr3+ recognition of QA could be achieved by means of fluorescense and absorption spectra, moreover, the obvious color change from colorless to yellowish is easily observed by naked-eyes. The binding constant of QA to Cr3+ was evaluated by spectral titration and the binding model was in 1:1 stoichiometry measured by Job's plot.