Enantioselective aptameric molecular recognition material: Design of a novel chiral stationary phase for enantioseparation of a series of chiral herbicides by capillary electrochromatography

Abstract

A chiral stationary phase derived from an L-RNA aptamer is evaluated for the enantiomer separation of a series of herbicide molecules (aryloxypropionic, aryloxyphenoxypropionic, and aminopropionic acid) by CEC after binding to biotin and grafting upon streptavidin-modified porous glass beads. We demonstrated that the aptamer capillary was stable in term of efficiency and retention during a long period. The influences of the mobile phase constitution and its flow-velocity on the enantioseparation were also investigated. The results suggest that the interactions of the enantiomer during CEC are solely based on chromatographic mechanisms and that the electrophoresis plays only a minor role. The separation efficiency and peak shape could be improved by Mg2+ divalent cation that stabilized the aptamer secondary structure and thus enhanced the mass transfer kinetics during the ligand-aptamer binding process. In addition, it was demonstrated that the determination of the enantiomerization barrier of flamprop was possible using this chiral stationary phase.

Recent applications in CEC

“…With samples of alprenolol and propanolol with 1:100 and 1:1000 ratios of the enantiomers complete separations could be obtained and a quantitative determination of the minor compounds was shown to be possible. Andre et al [22] developed a chiral stationary phase based on aptameric recognition. They bound a biotinylated RNA aptamer on 3.5 mm silica particles.…”

Enantioselective capillary electrochromatography: Recent developments and new trends

“…In [42], an RNA aptamer-based CSP was prepared and evaluated for enantioselectivity towards eight chiral herbicides. The CSP was prepared by binding an L-RNA aptamer to biotin and grafting upon streptavidin-modified silica particles.…”

Enantioseparation and Enantioselective Analysis of Chiral Herbicides

“…A series of herbicide molecules (haloxyfop, fluazifop, fenoxaprop, and flamprop free acids, diclofop, MCPP, DCPP, fenoprop, 2-PPA) were separated using a CSP derived from an L-RNA aptamer by CEC after binding to biotin and grafting upon streptavidin-modified porous glass beads. (Andre et al, 2006) A porous monolithic chiral column was prepared by in situ copolymerization of glycidyl methacrylate, methyl methacrylate and ethylene glycol dimethacrylate in the presence of formamide and 1-propanol as the porogen solvents to analyze the DCPP enantiomers.…”