The potential gradient measured by the ion electrode method is impacted by the temperature of the sample solution in accordance with the Nemst equation. The higher the temperature is, the larger the potential gradient is. The lower the temperature is, the smaller the potential gradient is.The standard solution in calibration and sample solution in measurement shall have almost the same temperature. Match the temperature as close as possible.
Relationship between temperature of ion selective electrode and theoretical slope
| Temperature（℃） | ||||||||
|---|---|---|---|---|---|---|---|---|
| 0 | 10 | 20 | 25 | 30 | 40 | 50 | ||
| Theoretical slope | Monovalent ions | 54.20 | 56.18 | 58.16 | 59.16 | 60.15 | 62.13 | 64.11 |
| Divalent ions | 27.10 | 28.09 | 29.08 | 29.58 | 30.07 | 31.07 | 32.06 | |
Unit: mV/decade (mV/concentration change of 10 times)