Ratiometric Detection Of Hg2 Research Articles

Cu2+-assisted sensing of fungicide Thiram in food, soil, and plant samples and the ratiometric detection of Hg2+ in living cells by a low cytotoxic and red emissive fluorescent sensor

Metal ions and pesticides are extensively used in many industries and agriculture. However, they cause significant environmental pollution and various adverse health effects. Therefore, the development of sensitive and selective techniques to detect them is necessary for human health and the ecosystem. In this paper, we report a novel red-emitting fluorescence probe with a large Stokes shift (∼220 nm) based on rhodamine and isophorone units. The probe shows a ratiometric fluorescence response toward Hg2+ ions; however, Cu2+ ions quench the red fluorescence signal. The decomposition of the probe-Cu2+ complex allows detection of Thiram followed by recovery of the red fluorescence signal of the probe. In addition, the probe shows a good linear response to Hg2+, Cu2+, and Thiram, with detection limits of 122.0 nM, 29.0 nM, and 72.0 nM, respectively. The practical applicability of the probe has been successfully tested in real samples. Moreover, smartphone detection and light-responsive capsule fabrication have been established, for easy and quick detection. The probe possesses very low cytotoxicity and allows visualization of Hg2+ and Cu2+ ions in HeLa cells. Therefore, the present probe is expected to be an effective tool assisting in easy, quick, and reliable detection of Thiram, Hg2+, and Cu2+ ions.

A new ratiometric fluorescent chemodosimeter for sensing of Hg2+ in water using irreversible reaction of arylboronic acid with Hg2+

We synthesized a highly selective ratiometric fluorescent chemodosimeter (1) for Hg2+ on the basis of the displacement reaction of phenylboronic acid with Hg2+ ions. The fluorescent chemodosimeter sensitively detected Hg2+ ions by two emission maxima with a 100 nm different wavelength. 1 exhibited remarkable detection property for Hg2+ such as high selectivity, high sensitivity, large fluorescent signal changes, ratiometric detection, and well-operation in aqueous solutions. Especially, the coexisting other metal ions did not interfere considerably with the ratiometric detection of Hg2+. The binding mode study indicated that the displacement reaction of 1 with Hg2+ provided the covalent adduct (2) of mercury ion, which aggregated in aqueous solution, resulting in the large fluorescent signal changes. Utilizing the ratiometric chemodosimeter with the low detection limit (15.2 nM) for Hg2+, nanomolar concentrations (0∼350 nM) of Hg2+ was successfully detected in aqueous solutions. 1 provided a ratiometric fluorescent detection method to quantify low levels of Hg2+ in groundwater and tap water samples.

Highly selective and sensitive ratiometric near-infrared fluorescent probe for real-time detection of Hg2+ and its bioapplications in live cells

A ratiometric near-infrared (NIR) fluorescent probe L based on chromenylium-cyanine fluorophore with chelate unit NS2O2 for the detection of Hg2+ ions in aqueous media has been prepared. The probe L shows high selectivity for Hg2+ ions with immediately fluorescence intensity increasing at 663 nm and decreasing at 728 nm synchronously via a Hg2+-induced intramolecular charge transfer (ICT) mechanism, leading to both “naked-eye” and ratiometric detection of Hg2+ ions in real time. At the same time, the probe exhibits a high sensitivity to Hg2+ in a concentration of ppb range with detection limit of 9.59 nM. Moreover, the probe is cell permeable and low toxic, and can be used in living cells for ratiometric visual monitoring of Hg2+ ions by confocal laser scanning fluorescence microscopy.

A Method for the Highly Selective, Colorimetric and Ratiometric Detection of Hg(2+) in a 100% Aqueous Solution.

Mercury (Hg) and its derivatives pose a serious threat to the environment and human health. Thus, the development of methods for the selective and sensitive determination of Hg(2+) is very important to understand its distribution, and to implement more detailed toxicological studies. Herein, we developed a new method for the detection of Hg(2+) based on the tricyanoethylene derivative and mercaptoethanol. This method could selectively detect Hg(2+) in a 100% aqueous solution by the naked-eye within the range of 1 - 60 μM. Importantly, this method also could detect Hg(2+) quantitatively by ratiometic absorption spectroscopy in the range of 0.1 - 6 μM with a detection limit of 55 nM. We anticipate that this proposed method will be used widely to monitor Hg(2+) in the environment.

A highly selective and ratiometric fluorescence probe for the detection of Hg2+ and pH change based on coumarin in aqueous solution

A simple but highly selective coumarin-based fluorescence probe 1, 8-(1,3-dithiane)-7-hydroxycoumarin was designed and synthesized for both the ratiometric detection of Hg2+ and the on–off response to pH change in aqueous solution. The sensor detected Hg2+ selectively via Hg2+-promoted thioacetal deprotection reaction within five minutes and reflected pH in the range from 7.8 to 11.9 as a result of the equilibrium between weak-fluorescent acid form and strong-fluorescent base form. In addition, the probe has an excellent selectivity towards Hg2+ over other competitive metal ions for biomedical and environmental applications. The sensing behavior of our probe was studied by UV–visible absorption spectra and fluorescence spectra.

Ratiometric detection of Hg2+ ions: an allosterically synchronized Hg2+/Li+ switch based on thiacalix[4]crown

A new heteroditopic chemosensor based on the 1,3-alternate conformation of thiacalix[4]crown shows a ratiometric fluorescence response towards Hg(2+) ions. Further, a negative allosteric behaviour between Hg(2+)/Li(+) ions is observed. Thus, metal ion exchange triggers a Hg(2+)/Li(+) switchable fluorescent chemosensor.