A Fluorescent Chemosensor Based on Schiff Base for the Determination of Zn2+, Cd2+and Hg2.

Abstract

Metal complexes were obtained by the reaction of zinc, cadmium and mercury(II) salts with Schiff base HL (N(salicylidene)benzylamine). HL was synthesized by the condensation reaction of benzylamine and 2-hydroxybenzaldehyde. The fluorescence properties of the Schiff base and its metal complexes were studied in ethanol-water solutions. HL was examined for its utility as a fuorescent chemosensor for the determination of Zn2+, Cd2+ and Hg2+ in aqueous samples. The HL chemosensor was found to be sensitive to Zn2+, Cd2+ and Hg2+ than some metal ions and its complexes emitted strong fluorescence at 452 nm for Zn2+ at 474 nm for Cd2+ and at 491 nm for Hg2+, respectively. It was determined that HL forms complexes with a ratio of 2:1 for Zn2+ and Hg2+ and with a ratio of 1:1 for Cd2+ by Job plots. For the detection of Zn2+, Cd2+ and Hg2+ in aqueous samples, pH, solvent type and ligand concentration were optimized for an analytical method based on HL chemosensor. HL gave a wide range of linearity with Zn2+, Hg2+ and Cd2+, the limit of detection was found to be 2.7 × 10-7 M, 7.5 × 10-7 M and 6.0 × 10-7 M, respectively.