Synthesis of sulfonamide based chemosensor for sensing of toxic Hg2+ ions in soil extract

Abstract

Schiff base (3) was synthesized through single step condensation of sulfanilamide and isatin and characterized with 1H NMR, 13C NMR, FT-IR and mass spectrometry analysis. The probe (3) was evaluated as the fluorometric and colorimetric sensor for toxic Hg2+ ions in semi aqueous medium. The LOD and LOQ were found to be 110 and 368 nM, respectively for Hg2+ ions. Binding stoichiometry of the (3):[Hg2+] was establised to be 1:1 (with B-H and Job’s plot), which was also supported by mass spectrometry. Computational studies (TD-DFT) further confirmed the complexation of the (3) and Hg2+ ions with UPBEPBE/6-311G (d.p) level of theory. Finally recuperation studies of probe (3) were carried out with the help of EDTA and showed reusability of (3) upto 6 cycles. Also these studies assist to develp a INHIBIT molecular logic gate. The probe (3) was practically used against spiked soil extract samples and resulted good amount of recovery.