Chiral Recognition of Tryptophan Enantiomers Based on β‐Cyclodextrin‐platinum Nanoparticles/Graphene Nanohybrids Modified Electrode

Abstract

The nanohybrids which based on β‐cyclodextrin, platinum nanoparticles and graphene (β‐CD‐PtNPs/GNs) were successfully synthesized and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FT‐IR) and electrochemical impedance spectroscopy (EIS). Then they were used to construct a simple and reliable chiral sensing platform to interact with tryptophan (Trp) enantiomers. Differential pulse voltammetry (DPV) was used to investigate the stereo selectivity of β‐CD‐PtNPs/GNs to Trp enantiomers. After interaction, the obvious difference of peak currents of L‐Trp and D‐Trp was obtained, indicating this strategy could be employed to chiral recognition of Trp enantiomers. Under the optimum conditions, the chiral sensor exhibited a good linear response to Trp enantiomers in a linear range of 5.0×10−5 to 5.0×10−3 M with a low limit of detection of 1.7×10−5 M (S/N=3). This approach provided a new available platform to recognize and determine Trp enantiomers.

Chiral Graphene Hybrid Materials: Structures, Properties, and Chiral Applications

“…Cyclodextrins, frequently used in the form of α ‐, β ‐, and γ ‐cyclodextrins ( α ‐CD, β ‐CD, and γ ‐CD, respectively [ 81 ] ), constitute another prevalent category of chiral sources for chiral functionalization of both graphene and GO. Nonetheless, obviously different from amino acids, cyclodextrins are incorporated with graphene and the derivatives much more through noncovalent interactions [ 82–86 ] rather than covalent bonding, [ 87–89 ] probably because of the relatively more difficulties in accomplishing reactions between cyclodextrins and graphene. Another reason may lie in the fact that substitution of the initial OH groups on cyclodextrins may exert influence on their enantioselectivity and the ability to form inclusion complex with guest compounds.…”

“…The resulting electrode could recognize tryptophan enantiomers. [ 86 ] Other chiral hybrids exploited following the similar idea are RGO/ β ‐CD/CPE (carbon paste electrode) for electrochemically sensing moxifloxacin hydrochloride enantiomers; [ 97 ] RGO/ β ‐CD/MB/GCE (MB, methylene blue) for electrochemically sensing chiral carboxylic acids; [ 98 ] RGO/ β ‐CD for electrically and optically sensing tryptophan enantiomers; [ 87 ] RGO/PNP/ β ‐CD/CPE (PNP, platinum nanoparticles) for electrochemically sensing chiral clopidogrels; [ 99 ] RGO/PTCA/ β ‐CD (PTCA, 3,4,9,10‐perylene tetracarboxylic acid) for electrochemically recognizing chiral phenylalanine; [ 100 ] RGO/ferrocene/ β ‐CD for electrochemically recognizing phenylalanine racemate. [ 101 ] These studies evidently show the importance of electrochemical sensors for enantio‐differentiating chiral compounds, due to their merits particularly in easy and fast operation.…”

β‐Cyclodextrin coupled to graphene oxide supported on aminopropyl silica as a sorbent material for determination of isoflavones

“…The coupling of CD to GO has also been successfully employed as electrochemical sensors [9]. The composite produced in this way incorporates the advantages of both the cyclodextrin and the graphene oxide nanoparticles [10].…”

Molecular recognition of N-acetyltryptophan enantiomers by β-cyclodextrin

“…The guest NAcTrp has been selected because of its large aromatic side chain with appropriate dimensions to fit tightly in the β-CD cavity thus expected to have restricted mobility and limited disorder. Indicative of the interest and possible applications of the CD use in chiral selectivity/discrimination of tryptophan are studies in aqueous solution [ 21 ], in electrochemistry for sensor development [ 17 , 22 – 23 ], as components of solid phases in chromatography [ 24 ], or in capillary electrophoresis [ 25 ].…”