文摘
Minor ion fluxes across ion-selective membranes biassubmicromolar activity measurements with conventionalion-selective electrodes. When ion fluxes are balanced,the lower limit of detection is expected to be dramaticallyimproved. As proof of principle, the flux of lead ionsacross an ETH 5435 ionophore-based lead-selectivemembrane was gradually compensated by applying a fewnanoamperes of galvanostatic current. When the oppositeion fluxes were matched, and the undesirable leaching ofprimary ions was eliminated, Nernstian response downto 3 × 10-12 M was achieved.