3D Nitrogen and Sulfur Co-Doped Graphene/Integrated Polysaccharides for Electrochemical Recognition Tryptophan Enantiomers

Abstract

Polysaccharides based on carboxymethyl β-cyclodextrin (β-CD-COOH) and chitosan (CS) were synthesized by amidation reaction between -COOH on β-CD-COOH and -NH 2 on CS to develop the electrochemical sensors. The sensor was constructed by combining the advantages of the polysaccharide CS-β-CD and the guest molecule and the 3D N, S co-doped graphene (NSG). CS-β-CD was used as chiral selector can provide a large number of chiral sites and NSG served as base material can improve electrochemical signal. The enantioselectivity of the chiral platform for tryptophan (Trp) enantiomers was studied by differential pulse voltammetry (DPV). NSG/CS-β-CD modified GCE showed higher electrochemical signal for L-Trp than D-Trp. When forming diastereoisomeric enantiomer-selector complexes between Trp isomers and NSG/CS-β-CD, there showed different steric hindrances, which made it easier for L-Trp to penetrate the modified electrode film to reach the electrode surface, thus producing a larger peak current. UV-vis further proved that CS-β-CD has higher binding energy to D-Trp. In addition, the proposed electrochemical sensor can be used to detect actual samples. Therefore, the proposed electrochemical chiral interface can be used as a promising chiral sensing platform for enantiomer recognition of chiral compounds.

A chiral sensing platform based on a multi-substituted ferrocene–cuprous ion complex for the discrimination of electroactive amino acid isomers

“…28 The N 1s spectra can be deconvoluted into two peaks at 399.7 and 402.0 eV (Fig. 5C), which are related to CN 29 originating from the metal precursor ([(CH 3 CN) 4 Cu]PF 6 ) and C–N 30 originating from Taniaphos, respectively. The P 2p spectra can be divided into three peaks at 130.9, 132.4 and 136.1 eV (Fig.…”

Ion-Induced Synthesis of Crystalline Carbon Nitride Ultrathin Nanosheets from Mesoporous Melon for Efficient Photocatalytic Hydrogen Evolution with Synchronous Highly Selective Oxidation of Benzyl Alcohol

“…Apparently, there are no peaks for cMel-5, indicative of the non-existence of S in accordance with the EDS results. However, for cMel, there are two distinct peaks at BEs of 169.1 and 168.0 eV, corresponding to S 2p 1/2 and 2p 3/2 of SO, 41 respectively, and the peak position of cMel is ∼0.1 eV higher than that of Mel (Figure S5a). Figure 3d shows the O 1s corelevel spectra of samples.…”

Single-Layer Graphene Oxide-Amino-β-Cyclodextrin/Black Phosphorus Nanosheet Composites for Recognition of Tyrosine Enantiomers

“…The quantity of dissociative polar functional groups at the electrode interface was reduced, resulting in weakened wettability. In addition, the WCAs of BPNSs/GCE (Figure S6B), NH 2 -βCD/GCE (Figure S6C), SGO/GCE (Figure S6D), SGO-NH 2 -βCD/GCE (Figure S6E), and SGO-NH 2 -βCD/BPNSs/GCE (Figure S6F) in l -Tyr were smaller than those in d -Tyr, which indicated that the sensor interfaces possessed higher affinity toward d -Tyr than l -Tyr. , Importantly, the WCA of SGO-NH 2 -βCD/BPNSs/GCE immersed in l -Tyr and d -Tyr solutions increased to 69.00 and 82.38°, respectively, which might be due to the more suitable intermolecular distance and the preferably formed hydrogen bonds between d -Tyr and SGO-NH 2 -βCD/BPNSs, and SGO-NH 2 -βCD/BPNSs/GCE immersed in d -Tyr would show a relatively higher WCA . Furthermore, the differences in WCA of SGO-NH 2 -βCD/BPNSs/GCE impregnated in l -Tyr and d -Tyr were the largest, indicating that SGO-NH 2 -βCD/BPNSs/GCE possessed the highest ability to recognize Tyr enantiomers, which was consistent with the SWV results.…”

“…However, the conductivity of β-CD is relatively lower, while the combination of β-CD with conductive nanomaterials could greatly improve its electrochemical performance . Meanwhile, the dispersibility of composite materials were also found to be greatly improved and could be rationally regulated .…”