A novel enhanced fluorescence method based on multifunctional carbon dots for specific detection of Hg²⁺ in complex...

Carbon quantum dots (CQDs), especially originated from biomass, have emerged as a rising star for the construction of metal ion sensor because they can serve as sensitive, selective and biocompatible probes. The present work describes a novel kind of ascorbic acid (AA)-enhanced CQDs which are synthesized with a kind of famous green teas, Maojian, serving as carbon source. Compared with the CQDs only based on Maojian teas, citric acid (CA)-enhanced and ascorbic acid (AA)-enhanced CQDs had the enhanced fluorescence intensity, and different response characteristics. In addition, the (AA)-enhanced CQDs showed more sensitive and specific fluorescence response to Hg²⁺ than simple ones, with a detection limit of 6.32 × 10^-9 nmol·L^-1. A linear response range from 2.00 × 10^-7 mol·L^-1 to 6.00 × 10^-5 mol·L^-1 was also achieved. The (AA)-enhanced CQDs also demonstrate good stability. They could effectively sense the Hg²⁺ in complex samples including waste water, tea and rice. Therefore, these versatile (AA)-enhanced CQDs fluorescence method hold a promising potential in other promising applications such as pharmaceutical quality, environmental quality, and food safety monitoring.