A Liquid/Liquid-Type Heteropolyanion Reference Electrode for Ion-Transfer Voltammetry

抄録

A new liquid/liquid-type reference electrode for ion-transfer voltammetry with the nitrobenzene (NB)/water (W) interface has been developed. This reference electrode is expressed as Pt/1.8 mM α-[SiMo₁₂O₄₀]^4- + 0.2 mM α-[SiMo^V₂Mo₁₂O₄₀]^4- + 0.1 M H₂SO₄ (W)/0.3 mM α-[SiMo₁₂O₄₀]^4- + 0.02 M tetrahexylammonium tetraphenylborate (NB). The Galvani potential difference between the reference NB/W interface is determined virtually by the distribution equilibrium of the heteropolyanion (α-[SiMo₁₂O₄₀]^4-), whereas the Pt electrode potential is determined by the redox equilibrium of the heteropolyanion couple. With this reference electrode, a potential window of about 0.4 V is available in a fairly negative potential region, where the transfer of hydrophilic inorganic anions (Br^-, I^-, SCN^-, NO₃^-, and ClO₄^-) can be observed voltammetrically.