Competitive Self-Assembly Interaction between Ferrocenyl Units and Amino Acids for Entry into the Cavity of β-Cyclodextrin for Chiral Electroanalysis

Anal Chem. 2022 Apr 19;94(15):6050-6056. doi: 10.1021/acs.analchem.2c00777. Epub 2022 Apr 7.

Abstract

At present, chiral electroanalysis of nonelectroactive chiral compounds still remains a challenge because they cannot provide an electrochemical signal by themselves. Here, a strategy based on a competitive self-assembly interaction of a ferrocene (Fc) unit and the testing isomers entering into the cavity of β-cyclodextrin (β-CD) was carried out for chiral electroanalysis. First of all, the Fc derivative was directly bridged to silica microspheres, followed by inclusion into the cavity of β-CD. As expected, once it was modified onto the surface of a carbon working electrode as an electrochemical sensor, SiO2@Fc-CD-WE, its differential pulse voltammetry signal would markedly decrease compared with the uncovered Fc. Next, when l- and d-isomers of amino acids that included histidine, threonine, phenylalanine, and glutamic acid were examined using SiO2@Fc-CD-WE, it showed an enantioselective entry of amino acids into the cavity of β-cyclodextrin instead of Fc, resulting in the release of Fc with signal enhancement. For histidine, glutamic acid, and threonine, l-isomers showed a higher peak current response compared with d-isomers. The peak current ratios between l- and d-isomers were 2.88, 1.21, and 1.40, respectively. At the same time, the opposite phenomenon occurred for phenylalanine with a peak current ratio of 3.19 between d- and l-isomers. In summary, we are assured that the recognition strategy based on the supramolecular interaction can enlarge the detection range of chiral compounds by electrochemical analysis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids*
  • Electrochemical Techniques / methods
  • Glutamates
  • Histidine
  • Phenylalanine / analysis
  • Silicon Dioxide
  • Stereoisomerism
  • Threonine
  • beta-Cyclodextrins* / chemistry

Substances

  • Amino Acids
  • Glutamates
  • beta-Cyclodextrins
  • Threonine
  • Phenylalanine
  • Histidine
  • Silicon Dioxide