Differentiation and determination of metal ions using fluorescent sensor array based on carbon nanodots

- The sensor array for metal ions was constructed by using carbon nanodots (CDs).
- It cost less than ten minutes to prepare CDs and construct the sensor array.
- The original hexa-sensor array can be simplified to binary-sensor by using principal component analysis method.
- The optimal pH and metal ion concentration range have been explored.
- Unknown metal ions can be determined in simulated fetal calf serum and local running water environments.

In chemical and biological sensing research, design and preparation of various sensors is a question of first importance. Generally, fabrication of specific sensors always requirs amounts of time-consuming and low-efficient synthetic tasks. Herein, a novel sensor array based on carbon nanodots (CDs) was constructed to differentiate and detect metal ions (including Ag+, Cd2+, Cr2+, Fe3+, Hg2+, and Pb2+), which utilized non-specific collective recognition reactions between CDs and various metal ions. The convenient synthetic methods and abundant carbon source greatly simplified the constructing process of the sensor array. Moreover, the hexa-sensor array can be simplified into binary-sensor array using principal component analysis (PCA) method. The binary-sensor array can be constructed in less than 10 min with competitive working performance as before. The binary-sensor array has its most comfort pH zone of around 5-10 and can perform well in the metal ion concentration of 50-1600 μM, suitable for the differentiation and determination of metal ions. The sensor array can also realize qualitative detection of unknown metal ions under the interference of a specific environment, including fetal calf serum and local running water.