A novel highly sensitive and selective optical sensor based on a symmetric tetradentate Schiff-base embedded in PVC polymeric film for determination of Zn2+ ion in real samples

A novel prepared Zn2+ ion PVC membrane sensor based on a novel Schiff base; N,N'bis(salicylaldehyde) 2,3-diaminonaphthalene (SDN) for the determination of Zn2+ ion was described. The chemosensor was synthesized under microwave irradiation via condensation of 2,3-diaminonaphthalene and salicylaldehyde. Photoluminescence characteristics of the novel Schiff base ligand were investigated in different solvents including dicholoromethane (DCM), tetrahydrofuran (THF) and ethanol (EtOH). SDN was found to have higher emission intensity and Stoke's shift value (Delta lambda(ST)) in EtOH solution. The sensor exhibited a specific fluorescent on response to Zn2+. The response of the sensor is based on the fluorescence enhancement of SDN (LH2) by Zn2+ ion as a result of formation the rigid structure L-Zn complex. The experiment results also show that the response behavior of SDN to Zn2+ is pH independent in the range of pH 6.0-8.0. At pH 7.0, the proposed sensor displays a calibration response for Zn2+ over a wide concentration range of 1.0 x 10(-9)-2.0 x 10(-3) mol L-1 with a limit of detection (LOD) 8.1 x 10-(10) mol L-1 (0.0529659 mu g L-1). The sensor shows excellent selectivity toward Zn2+ with respect to common coexisting cations. The proposed fluorescence optode was successfully applied to detect Zn2+ in human hair samples, different brands of powdered milk and some pharmaceuticals. (C) 2013 Elsevier B.V. All rights reserved.