Scanning Electrochemical Microscopy. 40. Voltammetric Ion-Selective Micropipet Electrodes for Probing Ion Transfer at Bilayer Lipid Membranes

摘要

Voltammetric ion-selective imicropipet electrodes for ue in scanning electrochemical microscopy(SECM)for detection of potassium ion were fabricated. These used pulled borosilicate capillaries with tip orifice radii of 0.7-20 #mu#m with silanized iner walls filled with a solution of 10 mM valinomycin and 10 mM ETH 500 in dichloroethane. The electrodes were characterized by determining the steady-state tip current for K~+ concentrations of 0.05-0.3mM. The tips were used in the SECM feedback and generation-collection modes to study K~+ transfer through gramicidin channels in a horizontal bilaryer lipid membrane(glycerol monooleate).