Rational design of highly enantioselective composite voltammetric sensors using a computationally predicted chiral modifier

Abstract

The use of chiral modifiers is among the simplest and most popular strategies for synthesizing enantioselective voltammetric sensors that are applied for the analysis and discrimination of enantiomerical drugs in various media. The type and structure of the chiral modifier are the key factors for the creation of enantioselectivity to a specified analyte. We suggest a novel approach to the prediction of the quality of a chiral modifier for preparing highly enantioselective sensors. The suggested approach is based on the molecular mechanics modeling of the adsorption of analyte enantiomers on chiral modifiers and on the comparison of the corresponding adsorption energies (ΔEads). The efficiency of our approach is demonstrated using the example of cyclodextrins and chiral single‐wall carbon nanotubes as chiral modifiers, and a wide range of chiral analytes. We found that the experimental enantioselectivity (ϑexp) measured using voltammetry linearly correlates with ΔEads. The suggested approach also showed good predictive power in application to enantioselective chromatography, which further validates its general applicability.

Chiral voltammetric sensor on the basis of nanosized MFI zeolite for recognition and determination of tryptophan enantiomers

“…A better enantiosensitivity of composite electrodes with MFI as a chiral modifier to Trp was predicted by theoretical simulations. According to the methodsuggested previously [42], let us compare the adsorption energies of L-Trp and D-Trp on MFI. The adsorption energies (Eads) calculated in Accelrys Material Studio v.8 [43] using the molecular mechanic approach were found to be Eads (D-Trp) = À 567.7 kJ/mol, Eads (L-Trp) = À 556.7 kJ/ mol, and it is D-Trp that is better adsorbed on MFI.…”

“…An important feature of enantioselective sensors based on chiral materials is that their sensitivity and detection limits depend on the effective area of the sensor surface. To increase the area of the sensitive layer of the sensor, porous materials with a developed surface are incorporated into composites, among which molecular sieves are of great interest [30, 31]. Molecular sieves have diverse structures differing both in pore size (CHA 3.8 Å, FAU 7.4 Å, VPI‐5 14 Å) and spatial organization of channels (1D MTT, 2D MFS, 3D MFI) [32].…”