Selective electrochemical determination of homocysteine in the presence of cysteine and glutathione

• Selective electrochemical determination of homocysteine.
• Catalytic electron transfer of 3,5-di-tert-buthylcatechol in the presence of homocysteine.
• Michael type addition reaction of electrochemically generated 3,5-di-tert-buthyl-o-benzoquinone with glutathione.

The electrochemical oxidation of 3,5-di-tert-buthylcatechol in the presence of homocysteine was used for the selective electrochemical determination of homocysteine in the presence of cysteine and glutathione at a glassy carbon and a glassy carbon electrode modified with carbon nanotube. The results revealed that the electrochemically generated 3,5-di-tert-butylcyclohexa-3,5-diene-1,2-dione exhibits high catalytic activity toward homocysteine oxidation at reduced over-potential and low catalytic activity for oxidation of cysteine. The catalytic activity 3,5-di-tert-butylcyclohexa-3,5-diene-1,2-dione toward cysteine was suppressed in the presence of 4-N,N-dimethylaminocinnamaldehyde. Contrary to homocysteine and cysteine, the reaction of glutathione with 3,5-di-tert-butylcyclohexa-3,5-diene-1,2-dione is a substituation reaction. This method exhibits three dynamic linear ranges of 2.5 to 10 μmol L−1, 10 to 100 μmol L−1 and 100 to 1000 μmol L−1, and a lower detection limit (3σ) of 0.89 ± 3.53% μmol L−1 for homocysteine.

3,5-Di-tert-buthylcatechol was used for the selective electrochemical determination of homocysteine in the presence of cysteine and glutathione at the glassy carbon and carbon nanotube modified glassy carbon electrode.Figure optionsDownload as PowerPoint slide