HgII-Selective Fluorescent Indicator: One-Step Synthesis

Biothiol-Functionalized Cuprous Oxide Sensor for Dual-Mode Sensitive Hg2+ Detection

Hg²⁺ ions are one of the highly poisonous heavy metal ions in the environment, so it is urgent to develop rapid and sensitive detection platforms for detecting Hg²⁺ ions. In this work, a novel electrochemical and photoelectrochemical dual-mode sensor (l-Cys-Cu₂O) was successfully fabricated, and the sensor exhibits a satisfactory detection limit (0.2 and 0.01 nM) for the detection of Hg²⁺, which is far below the dangerous limit of the U.S. Environmental Protection Agency. The linear ranges of dual-mode Hg²⁺ detections were 0.33-3.3 and 0.17-1.33 μM, respectively. Moreover, the sensor shows desirable stability, selectivity, and reproducibility for detecting Hg²⁺ ions. For river water samples, the recoveries of 96.6-101.4% (electrochemical data) and 93.0-105.6% (photoelectrochemical data) were obtained, indicating that the sensor could be successfully applied in the determination of Hg²⁺ ions in environmental water. Therefore, the designed sensor has a potential in the trace-level detection of Hg²⁺ ions.

Architecture of multi-channel and easy-to-make sensors for selective and sensitive Hg2+ ion recognition through Hg‒C and Hg‒N bonds of naphthoquinone-aniline/pyrene union

The aim of this work is, for the first time, to develop new inexpensive, easy-to-make and multi-channel receptors, naphthoquinone-aniline/pyrene union ((Nq-An) and (Nq-Pyr)) and their Hg²⁺ complexes [Hg-(Nq-An)₂] and [Hg-(Nq-Pyr)₂] to supply an efficient solution to critical deficiencies to be encountered for Hg²⁺ recognition. This study is based on colorimetric, fluorometric, and voltammetric methods for determination of Hg²⁺ ions through Hg-C and Hg-N binding mode of the naphthoquinone-aniline/pyrene union in aqueous media. The binding mode of the receptors with Hg²⁺ cation was confirmed by usual characterization techniques for the synthesized Hg²⁺-complexes [Hg-(Nq-An)₂] / [Hg-(Nq-Pyr)₂] and voltammetric, ¹H NMR titration experiments as well as Job's method, indicating a 2:1 complex between the receptors and Hg²⁺ cation. The receptors showed a considerable color switching from orange to pink along with a red-shift of absorption wavelength, and fluorescence enhancement via the Chelation Enhanced Fluorescence effect (CHEF), and distinctive changes on the voltammogram of the electroactive naphthoquinone unit with Hg²⁺ cation. The experiments indicate that the sensors are highly selective and sensitive toward Hg²⁺ among the studied metal ions in aqueous media compared with other reported Hg²⁺ sensors.

Accelerated hydration reaction of an unsymmetrical tolan evidenced by a Hg(ii)-trapped macrocycle and its application as a Hg(ii)-selective indicator

Hg(ii)-mediated hydration reactions of unsymmetrical quinoline type tolans were studied. The observed accelerated reactions of the tolans rely on the additional binding motifs of the tolan, as supported by the X-ray structure of the macrocycle (2b). The analyte-specific reaction allows us to detect Hg(ii) in buffered media.