Electrochemical Study of Dopamine at Electrode Fabricated by Cellulose-Assisted Aqueous Dispersion of Long-Length Carbon Nanotube

Hitoshi Muguruma, Yuki Inoue, Hitoshi Inoue, Tatsuya Ohsawa

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44 Citations (Scopus)


A long-length (hundred micrometers) carbon nanotube is successfully dispersed in aqueous solution with surfactant cellulose while maintaining its length. An electrochemical study of the synthetic pathway of dopamine (DA), dopamine-o-quinone (DAQ), leucodopaminechrome (LDAC), and dopaminechrome (DAC) at the electrode fabricated by the long-length carbon nanotube dispersed solution is presented. The sequence DA ⇌ DAQ ⇀ LDAC ⇌ DAC for the reaction is electron transfer-chemical reaction-electron transfer (ECE)-type, which is a chemical reaction (DAQ ⇀ LDAC, C) interposed between two electron transfer reactions (DA ⇌ DAQ and LDAC ⇌ DAC, E). The salient electrochemical signals due to both DA ⇌ DAQ and LDAC ⇌ DAC can be obtained at the long-length carbon nanotube electrode, unlike other carbon electrodes such as carbon paste, graphene, fullerene, nanofiber, and graphite. The overall reaction is dominated by step DAQ ⇀ LDAC and is sensitive to pH. With cyclic voltammetry in acidic media, the peak current due to LDAC ⇀ DAC disappeared at a higher scan rate because the reaction rate for DAQ ⇀ LDAC was so slow that DAQ was completely consumed in the electron transfer of DAQ ⇀ DA before the chemical reaction of DAQ ⇀ LDAC could go forward. In alkaline media, the peak height due to DAC ⇀ LDAC became as high as that due to DA ⇀ DAQ because the DAQ ⇀ LDAC rate became fast enough that a sufficient amount of LDAC was generated for the subsequent reaction of LDAC ⇀ DAC. Concomitantly, the reaction DAQ + LDAC ⇌ DA + DAC was generated. Quantitative and selective detection of dopamine based on the signal due to LDAC ⇀ DAC is possible just as in the conventional strategy of direct oxidation of dopamine (DA ⇀ DAQ).

Original languageEnglish
Pages (from-to)12284-12292
Number of pages9
JournalJournal of Physical Chemistry C
Issue number22
Publication statusPublished - 2016 Jun 9

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)


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