Ruthenium catalyst for amperometric determination of insulin at physiological pH

Waldemar Gorski, Craig A. Aspinwall, Jonathan R.T. Lakey, Robert T. Kennedy

Research output: Contribution to journalArticlepeer-review

70 Scopus citations


A ruthenium-oxide-type catalytic film (RuOx) was produced on carbon fiber microelectrodes by cycling the electrode potential between 0.65 and -0.85V vs. SSCE at 100 V s-1 in an air-equilibrated acidic solution of RuCl3. The film catalyzes oxidation of insulin in a saline buffer at pH7.4. The minimum number of electrons transferred during the insulin oxidation at 0.65 V is 6.7. The analytical performance of the modified electrode as an amperometric detector for insulin was characterized using flow injection analysis. Linear least squares calibration curves over the range 0.10 to 1.0 μM (five points) had slopes of 72 ± 2 pA μM-1 and correlation coefficients of 0.999 or greater. The detection limit, calculated as the concentration that would yield a signal equal to three times the root mean square noise, was 23 nM and response time (t90%) was 40ms or less. The electrode response to 0.2 μM insulin was stable for 3 days. The modified electrode was used for amperometric detection of exocytosis from individual pancreatic β-cells.

Original languageEnglish (US)
Pages (from-to)191-199
Number of pages9
JournalJournal of Electroanalytical Chemistry
Issue number1-2
StatePublished - Mar 30 1997


  • Amperometric detector
  • Exocytosis
  • Insulin
  • Physiological pH
  • Ruthenium catalyst

ASJC Scopus subject areas

  • Analytical Chemistry
  • Chemical Engineering(all)
  • Electrochemistry


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