Measurement of Hypoiodous Acid Concentration by a Novel Type Iodide Selective Electrode
and a New Method To Prepare HOI. Monitoring HOI Levels in the Briggs-Rauscher Oscillatory
Reaction
A new type of iodide selective electrode prepared by dipping a silver wire into molten
silver iodide is reported. The electrode was calibrated for silver and iodide ions
and the measured electromotive force for various Ag+ and I- concentrations was close
to the theoretical within a few millivolts. Besides Ag+ and I- ions, however, the
electrode also responds to hypoiodous acid. Thus, the electrode was calibrated for
HOT as well, and for that purpose a new method of hypoiodous acid preparation was
developed. To explain the close to Nemstian electrode response for HOI and also the
effect of hydrogen ion and iodine concentration on that response, the corrosion potential
theory suggested earlier by Noszticzius et al. was modified and developed further.
Following oscillations in the Briggs-Rauscher reaction with the new electrode the
potential crosses the "solubility limit potential" (SLP) of silver iodide. Potentials
below SLP are controlled by the concentration of I-, but potentials above SLP are
corrosion potentials determined by the concentration of HOI. Finally, the measured
HOI oscillations are compared with calculated ones simulated by a model by Furrow
et al.