Highly enantioselective discrimination of amino acids using copper deposition on a gold electrode modified with homocysteine monolayer

Mariko Matsunaga, Takuya Nakanishi, Toru Asahi, Tetsuya Osaka

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

An extremely enhanced enantioselectivity was achieved for the detection of enantiomers of alanine (Ala), leucine (Leu), and 3,4-dihydroxyphenylalanine (DOPA) based on the voltammograms for the deposition of Cu from Cu complexes of the amino acids at an Au electrode modified with a self-assembled monolayer (SAM) of l-homocysteine (Hcy). The enantioselective current density peak for the Cu deposition was found to change with increasing number of potential cycles after the addition of Cu(II), and the highest enantioselectivity was observed immediately after the addition of Cu(II). Besides, enantioselectivity was not observed with proline, whose five-membered ring contains the nitrogen atom of a secondary amino group, while some amino acids with a primary amine group such as Ala, Leu, and DOPA exhibited enantioselectivity. These results suggest that the chiral ligand exchange reaction at the l-Hcy SAM-modified Au electrode, namely, the enantioselective formation of diastereomeric complexes of Cu(II) with target enantiomers and l-Hcy self-assembled on the Au electrode, plays an important role in the chiral discrimination based on the Cu deposition.

Original languageEnglish
Pages (from-to)725-728
Number of pages4
JournalElectrochemistry Communications
Volume9
Issue number4
DOIs
Publication statusPublished - 2007 Apr

Fingerprint

Enantioselectivity
Homocysteine
Gold
Amino acids
Copper
Monolayers
Amino Acids
Dihydroxyphenylalanine
Electrodes
Enantiomers
Self assembled monolayers
Leucine
Alanine
Proline
Amines
Current density
Nitrogen
Ligands
Atoms

Keywords

  • Chiral discrimination
  • Chiral ligand exchange
  • Cu underpotential deposition
  • d-amino acids
  • Self-assembled monolayers
  • Solid/liquid interfaces
  • Voltammetry

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Analytical Chemistry
  • Electrochemistry

Cite this

Highly enantioselective discrimination of amino acids using copper deposition on a gold electrode modified with homocysteine monolayer. / Matsunaga, Mariko; Nakanishi, Takuya; Asahi, Toru; Osaka, Tetsuya.

In: Electrochemistry Communications, Vol. 9, No. 4, 04.2007, p. 725-728.

Research output: Contribution to journalArticle

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AB - An extremely enhanced enantioselectivity was achieved for the detection of enantiomers of alanine (Ala), leucine (Leu), and 3,4-dihydroxyphenylalanine (DOPA) based on the voltammograms for the deposition of Cu from Cu complexes of the amino acids at an Au electrode modified with a self-assembled monolayer (SAM) of l-homocysteine (Hcy). The enantioselective current density peak for the Cu deposition was found to change with increasing number of potential cycles after the addition of Cu(II), and the highest enantioselectivity was observed immediately after the addition of Cu(II). Besides, enantioselectivity was not observed with proline, whose five-membered ring contains the nitrogen atom of a secondary amino group, while some amino acids with a primary amine group such as Ala, Leu, and DOPA exhibited enantioselectivity. These results suggest that the chiral ligand exchange reaction at the l-Hcy SAM-modified Au electrode, namely, the enantioselective formation of diastereomeric complexes of Cu(II) with target enantiomers and l-Hcy self-assembled on the Au electrode, plays an important role in the chiral discrimination based on the Cu deposition.

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