Fig. 6 Relationship Between Monovalent Cation Concentration (Activity) And Electrode Potential - Horiba Scientific 6560S-10C Instruction Manual

If the ion concentration (activity) is set to the logarithmic axis, a linear
relationship like in the graph below is created between the electrode potential
measured with the ion selective electrode and the ion concentration (activity).

Fig. 6 Relationship between monovalent cation concentration (activity) and electrode potential

To perform the above quantitative analysis using an ion selective
electrode, either (1) use an ion meter or meter with an ion
measurement function that has a logarithmic arithmetic function or
Tip Tip
(2) create a calibration curve using semi-logarithmic graph paper.
∆2.303 RT/nF
Potential gradient
59.16 mV/decade (at 25ºC)
10 10
0
Ion concentration (activity)
2
59