A renewable electrochemical sensor based on a self-assembled framework of chiral molecules for efficient identification of tryptophan isomers.

Molecular self-assembly provides a reasonably effective strategy for the design and construction of chiral sensors. Here, Cu2+ was connected to β-cyclodextrin (β-CD) through coordination to synthesize Cu2-β-CD, subsequently assembled with ammoniated chitosan-MWCNTs (NH2-CS-MWCNTs) by the effect of coordination driver to form a chiral sensing interface Cu2-β-CD/NH2-CS-MWCNTs. Using the electrochemical method, the valid recognition of tryptophan (Trp) isomers was achieved on the self-assembly interface. Under the optimal experimental conditions, the developed sensor exhibited good linearity and satisfactorily renewable ability. Cu2-β-CD/NH2-CS-MWCNTs/GCE showed the capacity to predict the ratio of D-Trp and L-Trp in racemic mixtures and the possibility of qualitative and quantitative determination for Trp isomers. Finally, the electrochemical sensor was used to detect the Trp enantiomers in rat serum, further verifying the feasibility of the sensor in the determination of actual samples. Therefore, the electrochemical chiral sensor not only is used for the recognition of Trp enantiomers but shows great potential in practical applications.