Chiral Sensing Of Small Molecules Based On Carbon Nanomaterials And β-CD

Electrochemical chiral sensors is a new analysis method combining electrochemical sensors and chiral recognition, possessing a multitude of advantages such as high accuracy, high sensitivity, good selectivity, simple operation, low price with fast response and easy miniaturizationand automation. Carbon nanomaterials, as one of the most-used nanomaterials was used to modify glass carbon electrode and was used in the field of electrochemistry extensively because of its outstanding physical properties like excellent conductivity, large surface area and good stability. Cyclodextrins was combined of D- glucopyranose units by α-1,4-glucosidic bonds, toroidal in shape with special hydrophobic internal cavity and hydrophilic external surface, thus making it easily to form a stable inclusion complex with various guest molecules and acted as the most common chrial selector in chiral analysis. Based on the above consideration, this paper combined outstanding properties of carbon nanomaterials and cyclodextrins to construct electrochemical chiral sensor. The main researches are included as follows:1. A modified glassy carbon surface (β-CD/MWCNTs-IL/GCE) was constructed for chiral discrimination for DOPA enantiomers. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) had been used to measure the modified GCE. The results showed that the proposed chiral interface interacted with D-DOPA stronger than L-DOPA. In addition, the proposed interaction mechanism was investigated. Comparison of different electrochemical methods for recognition of DOPA was shown in table one, it was found that the constructed chiral sensor bebaved stronger selectivity, wider linear range and lower detection limit.2. A kind of nanomatierial (rGO@PtNPs) was synthesized in situ reduction. Then the composite was combined with L-tryptophan through π-π stacking. This obtained nanohybrid was modified on glassy carbon surface by one-pot synthesis to formed L-Trp-rGO@PtNPs/GCE. This chiral surface was used to interacte with DOPA enantiomers, it was found that this nanocomposite exhibited excellent properties and performed a stronger enantiospecificity for D-DOPA. And at the best condition, satisfactoried linear range and detection limit.3. Poly L-aspartic acid (P-L-Asp) films was got on glassy carbon electrodes via cyclic voltammetry (CV) technique. The as-prepared P-L-Asp-modified GCE was immersed into 0.01 M β-CD at room temperature overnight, thus chiral surface β-CD-P-L-Asp-/GCE was constructed, and it was to discriminate electroactive molecules-ascorbic acid enantiomers. The result indicated the chiral interface underwent stronger interaction with IAA, it can be concluded that ascorbic acid enantiomers was distinguished via β-CD-P-L-Asp/GCE. Further more, it still displayed strong selectivity toward ascorbic acid enantiomers even if interference molecules existed. To utilize the ineteractions between β-CD and ascorbic acid to construct a model to discriminate small electroactive molecules provided a simple method and reference in electrochemical analysis field.