Duration between the time when an ion-sele … Duration between the time when an ion-selective electrode and an external reference electrode (the two completing the ion-selective electrode cell) are brought into contact with a sample solution (or the time at which the activity of the ion of interest in solution is changed) and the first time at which the slope of the cell potential vs. time plot (ΔE/Δt) becomes equal to a limiting value selected on the basis of the experimental conditions and/or requirements concerning accuracy./or requirements concerning accuracy. +
