A nanomolar detection of mercury(II) ion by a chemodosimetric rhodamine-based sensor in an aqueous medium: Potential applications in real water samples and as paper strips

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2019-03, Vol.210, p.44-51
• Main Authors: Patil, Sagar K., Das, Dipanwita
• Format: Article
• Language: English
• Subjects: Chemodosimeter; Colorimetric; Fluorescent; Oxymercuration; Paper strip application
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2018.11.005

A new promising rhodamine based colorimetric and fluorometric chemosensor, RDV has been designed and synthesized for specific detection of Hg2+ ion. It acts as highly selective “turn-on” fluorescent chemosensor for Hg2+ ion without interference from other competitive metal ions in aqueous acetonitrile medium. The drastic color change with addition of Hg2+, from colorless to pink, indicates RDV can acts as “naked-eye” indicator for Hg2+. The Hg2+ promoted selective hydrolysis of appended vinyl ether group in RDV followed by Hg2+ chelated complex formation with concomitant opening of spirolactam ring is the plausible sensing mechanism. The detailed absorption, fluorescence, 1H NMR, 13C NMR and mass spectrometry confirms the proposed sensing mechanism. The limit of detection (LOD) of Hg2+ by RDV is 136 nM indicating the high sensitivity towards Hg2+. The RDV shows consistent spectroscopic response in biological pH range 4–10. In addition to explore practical applicability of RDV, its paper strips have been made and used to detect Hg2+ in pure water solution up to 10 ppm level. Furthermore, the potential application of RDV for the sensing of Hg2+ in real water samples (tap water and drinking waters from different sources) were also monitored and demonstrated. A rhodamine appended vinyl ether probe (RDV) for selective Hg2+ recognition has been synthesized which gives “turn ON” emission response for Hg2+ ion in aqueous medium over other metal ions in a chemodosimetric approach. The LOD is 136 nM. RDV has been explored for paper strip application as well as Hg2+ analysis from real water samples. [Display omitted] •A rhodamine appended vinyl ether probe (RDV) for selective Hg2+ recognition has been synthesized.•RDV gives “turn ON” emission response for Hg2+ ion in aqueous medium over other metal ions in a chemodosimetric approach.•The LOD value is as low as 136 nM.•RDV has been explored for paper strip application as well as Hg2+ analysis from real water samples.