title: Valinomycin-based K+ selective microelectrodes with low electrical membrane resistance.
abstract: A valinomycin-based membrane phase for microelectrodes with relatively low electrical membrane resistances is described. Microelectrodes with tip diameters of about 1 micron exhibit resistances of about 10(10) omega. Extremely high K+ selectivities are obtained, e.g. a rejection of Na+ by a factor of 5000 and of acetylcholine by a factor of 3400. At a constant background of 140 and 500 mM Na+, the detection limit of the K+ sensor is at 1.6 X 10(-5) and at 2.5 X 10(-5) M K+, respectively.
mesh_terms: D004553:Electric Conductivity; D004563:Electrochemistry / Q000295:instrumentation*; D008839:Microelectrodes; D009482:Neurophysiology / Q000295:instrumentation*; D011188:Potassium / Q000378:metabolism*; D014634:Valinomycin
chemical_list: D014634:Valinomycin; D011188:Potassium