Chemosensors with ultrasensing capabilities for detection of metal ions have received particular attention when using luminescent organic compounds. Even though hundreds of chemosensor agents have been reported for Fe3+ ion sensing, the designs of those molecules have been complicated and time consuming, in addition to having limited application for aquatic samples due to their poor hydrophilicity. Here, we synthesized a novel azo-imine derivative (L2) that showed ultrasensitive and selective sensing for Fe3+ ions. L2 exhibited ultraselective detection of Fe3+ ions with a turn-off of its emission intensity at 341 nm in H2 O:MeOH (4:1 v/v) aqueous medium. This quenching phenomenon was in good agreement with its colour change from orange-yellowish to colourless. Its capability was shown due to its very low limit of detection and limit of quantification values of 0.31 and 1.04 μM, respectively. The interference study showed that L2 is ultraselective for the detection of Fe3+ ions without a significant reduction in its sensing capability even in competitive metal mixtures. Furthermore, direct Fe3+ quantification of tap and drinking water showed that L2 gave good recovery percentages. These findings demonstrated that the Schiff's base with an azo fluorophore derivative is a potential chemosensor agent for Fe3+ ions sensing applications in aqueous media.
Keywords: Fe3+ ions; azo-imine; chemosensor; fluorescence; ultrasensitive.
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