A novel thioctic acid-carbon dots fluorescence sensor for the detection of Hg 2+ and thiophanate methyl via S-Hg affinity.

Mercury ions and thiophanate methyl (TM), are common contaminants present in the environment and food products. These contaminants cause neurovirulence and carcinogenicity effect on the human body. Herein, thioctic acid-carbon dots (SCDs) was synthesized and applied in a fluorescent "turn-off-on" probe to detect Hg ²⁺ and TM. The presence of other common metal ions and pesticides did not affect the response of the developed sensor. Further investigation revealed that the fluorescent "turn-off-on" model were static, wherein the "turn-off" was induced by an electron transfer effect, while the "turn-on" was caused by the formation of TM-Hg complexes. Under optimal conditions, the fluorescence sensor method exhibited limits of detection as low as 33.3 nmol/L and 7.6 nmol/L for Hg ²⁺ and TM, respectively. The developed sensor was designed to detect Hg ²⁺ and TM in real tap water, grape juice and Citri Reticulatae Pericarpium (CRP) water samples.
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