Fluorescence sensor array based on amino acid derived carbon dots for pattern-based detection of toxic metal ions

The development of convenient method for detection and identification of toxic metals ions is of great interest. In this work, we have developed a facile fluorescent sensor array based on luminescence carbon dots for detecting and differentiating a set of metal ions. Three kinds of nitrogen-doped carbon dots were synthesized by hydrothermal treatment of citric acid with three different amino acids (l-glycine, l-lysine and l-serine). These carbon dots had various surface states and thus exhibited diverse quenching responses to different metal ions. Six metal ions can be well distinguished at various concentrations (100, 50, 20 and 10 μM). The discrimination accuracy of unknown samples was found to be 100% at a concentration as low as 10 μM. In addition, the binary and ternary mixtures of three metal ions (Hg2+, Cu2+, Fe3+) could also be well recognized with this sensor array. This method is simple, label-free, and the sensor arrays could be obtained and expanded easily with large-scale and low-cost. It will broaden the application field of carbon dots sensors and give a new direction of developing sensitive array sensing systems.