Enhanced electrochemical enantiorecognition of tryptophan enantiomers based on synergistic effect of porous β-CD-containing polymers and multiwalled carbon nanotubes

Recent advances of the ionic chiral selectors for chiral resolution by chromatography, spectroscopy and electrochemistry

Ionic chiral selectors have been received much attention in the field of asymmetric catalysis, chiral recognition, and preparative separation. It has been shown that the addition of ionic chiral selectors can enhance the recognition efficiency dramatically due to the presence of multiple intermolecular interactions, including hydrogen bond, π-π interaction, van der Waals force, electrostatic ion-pairing interaction, and ionic-hydrogen bond. In the initial research stage of the ionic chiral selectors, most of work center on the application in chromatographic separation (capillary electrophoresis, high-performance liquid chromatography, and gas chromatography). Differently, more and more attention has been paid on the spectroscopy (nuclear magnetic resonance, fluorescence, ultraviolet and visible absorption spectrum, and circular dichroism spectrum) and electrochemistry in recent years. In this tutorial review as regards the ionic chiral selectors, we discuss in detail the structural features, properties, and their application in chromatography, spectroscopy, and electrochemistry.

Electrochemical chiral amino acid biosensor based on dopamine-localized gold nanoparticles @ left-handed spiral chiral carbon nanotubes

The high electrocatalytic performance plays a decisive role in the efficient electrochemical sensing of electrocatalysts. A spiral chiral carbon tube (HLCNT) loaded with gold nanoparticles (AuNPs) was prepared by electrochemical methods. Dopamine was first electropolymerized on the surface of the HLCNT, and then it acted as a localizer to uniformly load the AuNPs onto the surface of the HLCNT. The dopamine-localized gold nanoparticles @ left-handed spiral chiral carbon nanotubes (HLCNT-AuNPs-2) material combined the chiral structure of chiral carbon nanotubes and the high conductivity of AuNPs. The HLCNT-AuNPs-2 realized the qualitative and quantitative detection of tyrosine (Tyr) and tryptophan (Trp) isomers by their different oxidation potentials and current signals. Through quantitative detection, the analytical results showed that the detection limit of l-Trp was calculated to be 5.31 μM, and the detection limit of l-Tyr was 9.04 μM. More importantly, the material realized the real sample detection of amino acids, which is of great significance for the practical detection of amino acid isomers in medicine and biology.