Potentiometric sulfite biosensor based on entrapment of sulfite oxidase in a polypyrrole film on a platinum electrode modified with platinum nanoparticles

Samuel B. Adeloju, Shahid Hussain

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13 Citations (Scopus)


The surface of a platinum electrode has been modified with platinum nanoparticles (PtNPs) and the enzyme sulfite oxidase (SOx), was entrapped on its surface in an ultrathin polypyrrole (PPy) film. The PtNPs, with a diameter of 30–40 nm, were deposited on the Pt electrode by cycling the electrode potential 20 times from -200 to 200 mV at a sweep rate of 50 mV.s-1. Morphological evidence of the successful incorporation of SOx and the presence of PtNPs were obtained by scanning electron microscopy. Also, the electrochemical behavior of the PtNPs/PPy-SOx film was examined by cyclic voltammetry, chronopotentiometry, electrochemical impedance spectroscopy and potentiometry. Under optimized conditions, the biosensor achieved a sensitivity of 57.5 mV.decade-1, a linear response that extends from 0.75 to 65 μM of sulfite, a detection limit of 12.4 nM, and a response time of 3–5 s. The biosensor was successfully applied to the determination of sulfite in wine and beer samples.

Original languageEnglish
Pages (from-to)1341-1350
Number of pages10
JournalMicrochimica Acta
Issue number4
Publication statusPublished - 1 Apr 2016


  • Beer and wine analysis
  • Chronopotentiometry
  • Cyclic voltammetry
  • Electrochemical impedance spectroscopy
  • Enzymatic assay
  • Potentiometry
  • Scanning electron microscopy

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