A Fluorescent Chemosensor Based on Schiff Base for the Determination of Zn, Cdand Hg.

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 Zn, Cd and Hg in aqueous samples. The HL chemosensor was found to be sensitive to Zn, Cd and Hg than some metal ions and its complexes emitted strong fluorescence at 452 nm for Zn at 474 nm for Cd and at 491 nm for Hg, respectively. It was determined that HL forms complexes with a ratio of 2:1 for Zn and Hg and with a ratio of 1:1 for Cd by Job plots. For the detection of Zn, Cd and Hg 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 Zn, Hg and Cd, the limit of detection was found to be 2.7 × 10 M, 7.5 × 10 M and 6.0 × 10 M, respectively.