Studies On Electrochemical Sensors Based On Carbon Nanocomposites For Chiral Recognition Of Electroactive Molecules

Chirality is the common phenomenon in nature, and chiral compound is the basic component of living body. Different architectonic chiral compounds can exhibit distinct function in the field of medicine, life science, environment, food and materials industry. So the determination of the enantiomeric purity and the content of chiral compounds becomes a research hotspot in current chemistry. There is a new requirement that chial recognition technology is developing to the low cost and rapid detection. And the electrochemical sensor has been as a new test method for the study of chiral recognition based on the advantages of simple operation, rapid detection, sensitive response and low cost. Owing to their outstanding chemical stability, high accessible surface area, excellent electrochemical properties, carbon nanocomposites are widely used to construct the electrochemical sensing interface, which open a new prospect of electrochemical sensor for chiral recognition. This paper is to explore a novel chiral sensing plateform for chiral rcognition of electroactive molecules in real-time, online and rapid detection. The main research works are included as follows:1. A sensing interface with porous cluster-like nanocomposite films has been fabricated by electrochemical polymerization of L-cysteine on the surface of multi-walled carbon nanotubes (PLC/MWCNTs), and it was characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The nanocomposite films have been used to interact with tryptophan enantiomers (D- and L-Trp), and an obvious difference was achieved in the oxidation peak currents between D-Trp and L- Trp. The results demonstrated that the proposed sensing plateform exhibited excellent enantioselective recognition ability to tryptophan enantiomers, and it had a stronger interaction with D-tryptophan.2. A chiral sensing plateform has been constructed by the ionic liquid reduced graphene oxide (IL-rGO), the electrodeposition of gold nanoparticles (dpAu) and sulfhydryl-β-cyclodextrin (β-CD-SH). The differential pulse voltammetry (DPV) was used to investigate the interaction between the sensing inerface and the 3,4-dihydroxyphenylalanine (DOPA) enantiomers, and a larger peak current has been obtained from D-DOPA than L-DOPA. The results indicated that the proposed sensing plateform had a stronger interaction with D-DOPA.3. A novel electrochemical sensor was fabricated for enantioselective recongnizing 3,4-dihydroxyphenylalanine (DOPA) enantiomers based on a chiral nanocomposite. The chiral nanocomposite was synthetised by L-cysteine covalently binding with the muti-walled carbon nanotubes which were functionalized by 3,4,9,10-perylene tetracarboxylic acid (MWCNTs-PTCA-Cys). Square wave voltammetry (SWV) and cyclic voltammetry (CV) were employed to investigate the stereospecific interaction between the MWCNTs-PTCA-Cys nanocomposite and DOPA enantiomers. The results demonstrated that D-DOPA had a larger peak current than L-DOPA on the the proposed sensing plateform, and the SWV exhibited better recognition effect than CV.