Electrochemically Recognizing Tryptophan Enantiomers based on Carbon Black/Poly-l-Cysteine Modified Electrode

Abstract

Construction of efficient and convenient sensors for recognition of chiral enantiomers is of much significance in the field of electrochemistry and life sciences. Herein, we designed an effective chiral interface for the successful identification of tryptophan (Trp) enantiomers by electrodepositing l-cysteine on the surface of glass carbon electrode modified with carbon black. The structure and morphology of the prepared sensor was characterized by scanning electron microscopy (SEM) and electrochemical methods. Compared with l-tryptophan (L-Trp), the sensor exhibits favorable chiral recognition towards D-tryptophan (D-Trp) with a separation coefficient of 2.50. Compared with existing studies on electrochemical chiral recognition of Trp enantiomers, our designed chiral platform boasts of a wider linear range (1.0–1400.0 μM) and lower limits of detection thus, 0.33 μM and 0.45 μM for L-Trp and D-Trp respectively. In addition, the proposed sensor has the capacity to recognize chiral molecules in Trp isomers mixture and the potential for the identification of other amino acids.