A novel thioctic acid-carbon dots fluorescence sensor for the detection of Hg2+ 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 Hg2+ 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 turnoff 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 Hg2+ and TM, respectively. The developed sensor was designed to detect Hg2+ and TM in real tap water, grape juice and Citri Reticulatae Pericarpium (CRP) water samples.

Automated summary

Thioctic acid-carbon dots were synthesized and used as a fluorescent turn-off-on probe to detect Mercury ions and thiophanate methyl. The sensor showed no interference from other common metal ions and pesticides, and exhibited low detection limits for Hg2+ and TM. It was successfully applied for detecting Hg2+ and TM in real water samples.