Study of A Tridentate Schiff-Base as A Highly Selective Fluorescent Sensor for Detection of Copper and Chromium Ions

Abstract

A simple and easily synthesized fluorescent sensor, Schiff base sensor (SBS), produced by condensation reaction of equal amounts of anthranilic acid and salicyladehyde. It was synthesized and characterized systemically. Both UV-vis and fluorescence spectroscopic studies indicated that the SBS sensor showed good selectivity toward the studied ions: Na⁺, K⁺, Cu²⁺, Co²⁺, Fe³⁺ , Al³⁺ and Cr³⁺. Whereas, chromium (III) and copper (II) exhibited the largest fluorescence enhancement over the other investigated ions.

Chelation-enhanced fluorescence were shown upon the interaction of SBS sensor with some metal ions studied forming inclusion complexes. The fluorescent sensor in aqueous ethanolic solution exhibited high selectivity towards Cu²⁺ and Cr³⁺ ions, forming 2 : 1 (L : M) complex as determined by Job’s plot.

The formation constants of the inclusion complexes (Mⁿ⁺/SBS) were measured via spectrofluorometric method applying Benesi-Hildebrand equation.