Self‐assembled lipid bilayers as a potassium sensor

The effect of valinomycin on a novel bilayer lipid membrane (BLM) system supported on a metallic wire (s‐BLM) has been investigated. An increase in concentration of valinomycin from 6 × 10−6 to 6 × 10−4 mol L−1 increases the conductivity of the system after addition of potassium ions. A remarkable effect of the buffer medium on the electrode response has been observed, a solution of 0.1 M Tris‐HCl being most suitable. The assembled electrode system is stable for about 120 hours. A linear response toward potassium has been found in the range from 2.5 × 10−3 to 1.3 × 10−1 mol L−1. Effect of pH, temperature, and possibly interfering substances are reported.