A Novel Fluorimetric Bulk Optode Membrane Based on NOS Tridentate Schiff Base for Selective Optical Sensing of Al 3+ Ions

A novel fluorimetric optode has been developed for the highly selective and sensitive for the determination of ultra trace amounts of Al ions. The proposed fluorescent optode is based on the incorporation of a simple and effective fluorescent sensor tridentate NOS Schiff base N-(2-hydroxynaphthylidene)-2-aminothiophenol (H L) in a plasticized PVC containing KTpClPB as a lipophilic anionic additive. H L was synthesized by a facile one-step Schiff base reaction. The plasticized PVC-membrane displays a calibration response for Al ions over a wide concentration range from 1.0 × 10 to 4.4 × 10 mol/L. The fluorescence signal of the optode membrane can be easily recovered by immersion in 0.01 M EDTA. In addition to high stability and reproducibility, the sensor shows a unique selectivity towards Al ion with respect to common co-existing cations, particularly Ga and In . The proposed optode was applied successfully for determination of Al in some real samples, including bottled drinking waters, bottled mineral waters and soft drinks.