Electrochemiluminescent chiral discrimination with chiral Ag₂S quantum dots/few-layer carbon nitride nanosheets

Well-dispersed chiral Ag₂S quantum dots (Ag₂S QDs) were facilely synthesized by using N-acetyl-L-cysteine (NALC) as the chiral ligand and loaded onto nanosheets of two-dimensional (2D) few-layer carbon nitride (C₃N₄). The resultant nanocomposite (Ag₂S QDs/few-layer C₃N₄) shows enhanced electrochemiluminescence (ECL) while maintaining the chirality of Ag₂S QDs, which can be used for the chiral discrimination of the enantiomers of tyrosine (Tyr). Due to the higher affinity of chiral Ag₂S QDs toward L-Tyr than toward its enantiomer, the ECL intensity of Ag₂S QDs/few-layer C₃N₄ is significantly decreased after its incubation with L-Tyr, and thus the Tyr enantiomers can be discriminated. The developed ECL chiral sensor exhibits high stability and reproducibility. The universality of the ECL chiral sensor for the discrimination of other chiral amino acids is also studied, and the results indicate that it can work only in the case of chiral aromatic amino acids.