TY - JOUR
T1 - Highly enantioselective discrimination of amino acids using copper deposition on a gold electrode modified with homocysteine monolayer
AU - Matsunaga, Mariko
AU - Nakanishi, Takuya
AU - Asahi, Toru
AU - Osaka, Tetsuya
N1 - Funding Information:
This work was financially supported in part by “Special Coordination Funds for Promoting Science and Technology” and “the 21st Century COE program” of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. Mariko Matsunaga acknowledges the Grant-in-Aid for JSPS Fellows, MEXT. Assistance in manuscript preparation provided by Dr. Yutaka Okinaka is acknowledged.
PY - 2007/4
Y1 - 2007/4
N2 - 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.
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.
KW - Chiral discrimination
KW - Chiral ligand exchange
KW - Cu underpotential deposition
KW - Self-assembled monolayers
KW - Solid/liquid interfaces
KW - Voltammetry
KW - d-amino acids
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U2 - 10.1016/j.elecom.2006.10.046
DO - 10.1016/j.elecom.2006.10.046
M3 - Article
AN - SCOPUS:33947732195
SN - 1388-2481
VL - 9
SP - 725
EP - 728
JO - Electrochemistry Communications
JF - Electrochemistry Communications
IS - 4
ER -