Mercury ion (Hg2+) is a highly toxic environmental pollutant distributed widely in water, posing a substantial threat to human health. Thus, developing a sensitive and handy tool for Hg2+ onsite detection will be greatly beneficial for the prevention and control of Hg2+ pollution. Herein, CoTe2 was synthesized successfully as a novel mimic peroxidase. The peroxidase-like activity of CoTe2 was significantly enhanced by Hg2+ due to the strong combination of Te–Hg, causing improved generation of ·OH and activated oxidation of the chromogenic substrate 3,3′,5,5′-tetramethylbenzidine. From this, a colorimetric and electrochemical dual-mode sensor was developed for the detection of Hg2+, which presented wide linear ranges of 0.050–10.0 and 0.010–15.0 μM, with low detection limits of 16.7 and 3.3 nM, respectively. Additionally, the sensor is more conducive to Hg2+ detection in the environmental water samples with complex compositions due to its remarkable anti-interference ability originating from the specific binding of Te–Hg. Furthermore, a smartphone was utilized as a portable tool to achieve rapid onsite detection of Hg2+. Consequently, the proposed sensor has outstanding advantages of high sensitivity, good selectivity, and high practicality, showing considerable potential for the broad application of environmental water sample detection.
Liu et al. (Wed,) studied this question.