Figure 4.

Calculated composition of an ISE membrane based on ionophore 1 and 71 mol % ionic sites when exposed to 1 mM Cs⁺ and a varying activity of K⁺, corresponding to the K⁺ response in a Cs⁺ background shown in Figure 2: Membrane concentrations of (a) complexes between ionophore and K⁺ and Cs⁺, and (b) free ionophore and free K⁺ and Cs⁺ ions (note the logarithmic scale). All parameters used to calculate these concentrations are the same as for fit of the EMF in a Cs⁺ background, as shown in Figure 3 (broken line).