Periodate-selective liquid membrane electrode

Abstract

A liquid membrane electrode that responds to periodate ion is described. It incorporates a berberine-periodate ion-pair complex, dissolved in o-nitrotoluene, as the ion-exchange material. The electrode exhibits a near-Nernstian response for 10^–1–5.0 × 10^–5Mperiodate with a slope of 62 mV per activity decade. The static response time is 5–10 s, the working pH 1.5–7.5 and the limit of detection 2.5 × 10^–5Mperiodate. The selectivity towards the periodate ion relative to other common inorganic and organic anions is reasonably high. However, perchlorate and permanganate ions cause significant interference. The electrode was used successfully for the direct potentiometric determination of periodate in the presence of iodate and bromate.