Fluorescent sensing and determination of mercury (II) ions in water

Abstract

The presence of heavy metals released from industrial activities into water streams is an ever-growing challenge to ensuring a safe and clean aquatic environment. Detection and determination of the levels of these heavy metals in wastewater is an important step before any measures can be taken. In this study we report on a fluorescent sensing probe based on a naphthyl azo dye modified dibenzo-18-crown-6-ether (DB18C6) for the detection and determination of mercury (II) ions in water. The probe showed high sensitivity and selectivity towards the mercury (II) ion among various alkali, alkaline earth, and transition metal ions. The mercury (II) ion quenched the fluorescence of the probe. Stern-Volmer quenching constants (K sv ) were found to be highest for Hg 2+ ion at 1.18 x 10 5 M -1 compared to 3.85 x 10 4 M -1 for copper (II) ion. The stoichiometry of the sensormetal ion interaction was found to be 1:1 for both metal ions using Job plots. The detection limit for Hg 2+ was 1.25 x 10 -8 M. The dye modified crown ether was then used to detect mercury in a water sample from a coalfired power plant and to determine the amount of mercury in the water sample.

Supramolecular Luminescent Sensors

“…Transition metals have also been detected using modified crown ethers. Azo dye-appended 157 (Figure ) bound to Hg 2+ and Cu 2+ with 80% and 40% quenches of emission and Stern–Volmer constants of 1.18 × 10 5 M –1 and 3.85 × 10 4 M –1 , respectively, whereas neither K + nor Na + produced notable emission changes . A detection limit of 12.5 nM for mercury was found, and this technique was applied for mercury detection in industrial water runoff from a coal-fired power plant, in which a mercury concentration of 1.64 μM was determined.…”

Rapid detection of mercury contamination in water by surface enhanced Raman spectroscopy

“…K + , Li + , Na + , Ag + , Ca 2+ , Mg 2+ , Ba 2+ , Sr 2+ , Ni 2+ , Co 2+ , Cd 2+ , Pb 2+ , Cu 2+ , Fe 3+ , Al 3+ , La 3+ , Eu 3+ and Dy 3+ ) has been reported in literature. 22,23 In this work, cadmium(II) and Pb(II) ions were chosen for the selectivity studies using UV visible and uorescence spectroscopy because of the similar chemical properties between Cd(II), Pb(II) and Hg(II) and the fact that these toxic heavy metals are among the commonly known environmental pollutants. The UV absorption (Fig.…”

“…[19][20][21] The selective complexation of Hg(II) over a wide range of environmentally relevant metal ions by dibenzo 18-crown-6 azo dye derivatives using UV-visible and uorescence spectrometry has been reported in the literature. [22][23][24] In this work, a different mode of detection (i.e. SERS) with high sensitivity and a new aminodibenzo-18-crown-6 (ADB18C6) derivative was used.…”

Ion-induced cycle opening of a diarylethene and its application on visual detection of Cu2+ and Hg2+ and keypad lock

“…It indicated that photoinduced electron transfer between metal ion and organic ligand. 55,56 Then, to a red solution of PBC in PSS Cu 2+ or Hg 2+ ions was added. The red solution could also immediately bleach aer adding Cu 2+ or Hg 2+ ions.…”