Rapid determination of cadmium in Panax notoginseng using NCDs quantum carbon dots-aptamer fluorescence sensor

Cadmium is widely found in nature and excessive cadmium content in Chinese herbal medicine has become a common phenomenonis. For the human body, cadmium is a very harmful and toxic heavy metal, which will cause immeasurable harm to the liver and kidney. Panax notoginseng has been widely praised as a Chinese herbal medicine with many benefits to the human body. In order to avoid a series of safety problems caused by excessive cadmium content in Panax notoginseng , it is necessary to detect cadmium before it is used. Herein, a novel flueorescent aptasensor for the detection of cadmium in Panax notoginseng was developed by combining the carbon quantum dots NCDs prepared by one-step hydration of citric acid and ethylenediamine and the CD-4 aptamer. The aptamer-NCDs conjugation binds to the target cadmium, resulting in fluorescence quenching due to electrostatic interaction. Under certain conditions, the fluorescence intensity of cadmium decreases linearly with the increase of cadmium concentration and the LOD value of this method is 0.89 μg/L and LOQ value is 2.68 μg/L. After simple pretreatment of the actual sample of Panax notoginseng powder, this method was used to detect the cadmium. The accuracy and superiority of the proposed fluorescence aptasensor was verified by compared with ICP-MS method. This aptasensor with simple operation, high sensitivity, strong specificity provides a broad prospect for the detection of toxins in Chinese medicinal materials.