The role of bromine adlayer at palladium electrode in the electrochemical oxidation of dopamine in alkaline solution

Emad A. Khudaish, Muna R. Al Birikei

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

A palladium electrode modified with bromine monolayer was fabricated throughout a spontaneous oxidative chemisorption of bromide ions contained in an alkaline solution. The surface coverage and the apparent double layer capacitance induced by the adsorption of bromide ions under the present applied potential indicates the formation of incomplete monolayer due to a prominent co-adsorption of hydroxyl ions (OH-). The film modified electrode exhibited a substantial reactivity and high sensitivity in the electrochemical oxidation of dopamine (DA) in the presence of ascorbic acid (AA) and uric acid (UA). This trend was attributed to the structure and the composition of the bromine adlayer which renders a partial negative charge capable of attracting selectively the cationic DA and repelling anionic AA and UA. The peak currents of DA in the binary and ternary mixtures were well-separated, well-defined and increased linearly with respect to its concentration. The interference property expected by the presence of both AA and UA has been advantageously eliminated at the bromine-adlayer modified electrode. The apparent diffusion coefficient value of DA was 1.37 × 10-8 m2 s-1, based on an amperometric current-time study. The present system provides a simple and fundamental approach for the simultaneous and selective determination of DA in the presence of AA and UA.

Original languageEnglish
Pages (from-to)68-74
Number of pages7
JournalJournal of Electroanalytical Chemistry
Volume650
Issue number1
DOIs
Publication statusPublished - Dec 15 2010

Fingerprint

Bromine
Electrochemical oxidation
Palladium
Ascorbic acid
Dopamine
Uric Acid
Ascorbic Acid
Electrodes
Acids
Bromides
Monolayers
Ions
Adsorption
Time and motion study
Chemisorption
Capacitance
Chemical analysis

Keywords

  • Ascorbic acid
  • Bromine adlayer
  • Dopamine
  • Palladium modified electrode
  • Uric acid

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Analytical Chemistry
  • Electrochemistry

Cite this

The role of bromine adlayer at palladium electrode in the electrochemical oxidation of dopamine in alkaline solution. / Khudaish, Emad A.; Al Birikei, Muna R.

In: Journal of Electroanalytical Chemistry, Vol. 650, No. 1, 15.12.2010, p. 68-74.

Research output: Contribution to journalArticle

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