The range of the straight part of the standard curve is the Nernst response range (generally 10-1-10-6 mol/L), within which the slope of the straight line for monovalent ions should be 57-61mV/paI;

2. The selectivity coefficient is similar to that of glass electrodes.

3. Response time - the time required from electrode insertion to a stable potential value of ± 1mV.

4. Stability - represented by the change in potential over time.

5. Internal resistance - The internal resistance of selective electrodes is relatively high, generally ranging from 104 to 109 Ω. Use a potentiometer with high impedance.

6. Accuracy - represented by the relationship between the relative error of the analysis results and the measurement error of the electromotive force. When the measurement error is 1mV, the relative concentration error that may be caused by monovalent ions is about 4%; The divalent ion is about 8%.

Ionic electrodeThe ability to convert the activity of a specific ion in a solution into a certain potential, whose potential is linearly related to the logarithm of the given ion activity in the solution. The ion selective electrode is a membrane electrode, and its core component is the sensing membrane of the electrode.