Logic gate-based Rhodamine-methionine conjugate highly sensitive fluorescent probe for Hg~(2+) ion and its application: An experimental and theoretical study

摘要

A fluorescent, Hg2+selective sensor, based on a Rhodamine 6G and methionine conjugate (RGM) has been devised and synthesized. The compound was well characterized by analytical techniques like1H NMR, ESI–MS, FTIR, UV–vis absorption and fluorescence spectroscopy. The spectroscopic studies revealed that RGM displays a high selectivity and sensitivity towards Hg2+in presence of several other interfering metal ions in Tris-HCl buffer (10 mM, pH 7.04) containing CH3CN/H2O (1:1, v/v) by forming a 1:1 complex with Hg2+. The complexation of the probe RGM with Hg2+was also confirmed by ESI–MS and FTIR spectra. The detection limit of the probe RGM for Hg2+was found to be 2.63 × 10−8 M. The ligand RGM and RGM-Hg2+complex structures have been also established through theoretical studies. Moreover, the RGM-Hg2+complex was reversible in the presence of sulphide anions and thus RGM-Hg2+complex could also be used as an efficient sensor for S2−ions. The probe RGM was successfully applied for the detection of Hg2+in water samples, biological cells as well as in strip test.