Dansyl derivative turn off fluorescent probe for Al3+: Experimental and computational study in aqueous medium

Abstract

A dansyl derivative sensor termed as o-PDDS (N-(2-aminophenyl)-5-(dimethilamino)-1-naphtalenesulfonic amide) was prepared and studied for detection of Al3+ ions in aqueous medium. The synthesized sensor was characterized and confirmed by NMR, UV–Visible and fluorescence studies. The performance of the sensor against different inorganic ions was evaluated with greater sensitivity for aluminum. Then a computational study was performed to propose the stoichiometry ratio between Al(III)-(o-PDDS). The o-PDDS sensor showed good linear responses toward Al3+ ions at concentrations between 0.3-133.3 μM and limit of detection of 1.9 μM. The binding constant between Al3+ ions and o-PDDS has been determined by using both the Benesi-Hildebrand and Stern-Volmer equation, and the results indicated a static mechanism of quenching and high sensitivity of the o-PDDS to Al3+ ion. In line with experimental absorption and emission spectra, density functional theory calculations suggest a stoichiometry ratio between theo-PDDS and Al3+ of 1:1 in the complex Al(III)-(o-PDDS). Furthermore, the interference study and real sample assays of tap, distilled, and dialysis water exhibited satisfying results, which provides the possibility of developing a simple and efficient aluminum sensor for field use.