The Preparation of Cu(II)- and Ag(I)-responsive Carbon Nanodots from the Right Amino-acid Carbon Source.

Carbon nanodots (CDs) have exhibited excellent sensing capability for various metal ions. However, it is difficult to determine the selectivity of CDs to metal ions. In this work, we chose appropriate carbon source to design CD sensors against Cu(II) and Ag(I). Glycine, histidine and leucine have been confirmed to form complexes with Cu(II) and Ag(I), and were applied to prepare CDs using microwave heating method. The as-prepared CDs inherited the specific ion-binding capability from their carbon source and could response to both Cu(II) and Ag(I). The response sensitivity corresponded to the binding energy between the carbon source and metal ions. These experimental results are very important for the further design of CD sensors for a large variety of analytes.