A new liquid membrane electrode for the selective determination of perrhenate

A new perrhenate ion-selective electrode has been developed, incorporating a nitrobenzene solution of nitron perrhenate as a liquid membrane. The electrode gives near-Nernstian response to 3 x 10(-5)-10(-2)M perrhenate over the pH range 3-8. Most common anions (except for periodate and perchlorate) give little interference. The electrode has been satisfactory for direct potentiometric determination of as little as 10 mu/ml rhenium. The average recovery and standard deviation were 99% and 2.1%, respectively. Measurements of the solubility products of some sparingly soluble perrhenates gave results that agreed closely with those recorded in the literature and obtained by other procedures.