Answers to 3 common questions about pH electrodes
1. How long is the service life of the pH electrode?
Used correctly and maintained properly, the lifespan of a pH electrode can be expected to be around one to three years. Factors that can shorten the life of electrodes include: high temperatures and measuring under extreme pH conditions, which can shorten the life of even properly maintained electrodes. If electrode performance begins to degrade, the pH-sensitive glass membrane can be regenerated and the electrode performance restored to its original level.
2. How to choose the correct pH electrode?
To ensure optimal pH measurement results, it is important to select the correct pH electrode for each application. The most important sample criteria are: chemical composition, homogeneity, temperature, process pressure, pH range and container size (length and width limits). Electrode selection is particularly important for non-aqueous, low conductivity, protein-rich and viscous measurement media. In these samples, universal glass electrodes are susceptible to many different influences, leading to measurement errors. The response time and accuracy of the electrode depends on many factors. Measurements made at extreme pH values and temperatures or at low conductivity have longer response times than measurements made at room temperature for values in neutral pH aqueous solutions.
3. How to maintain/clean the electrode?
Routine maintenance is important to extend the life of your pH electrode. When the liquid level may be lower than the liquid level of the sample solution, it is necessary to add electrolyte to the electrode that can be filled with electrolyte. Maintenance prevents sample from flowing back into the electrode. The entire reference electrolyte should also be replaced regularly (approximately once a month). This ensures that the electrolyte is fresh and does not crystallize due to evaporation from the open filling port during the measurement. It is very important to ensure that no bubbles are generated inside the electrode, especially near the junction. If this occurs, the measurement results will become unstable. To remove air bubbles, gently shake the electrode like you would a thermometer.
To clean the electrode, rinse it with deionized water after each measurement, but never wipe it with paper towels. The paper towel surface has the potential to scratch and damage the pH-sensitive glass membrane, wipe off the gel layer, and create an electrostatic charge on the electrode. Such static charges can cause the measurement signal to become very unstable. Special cleaning procedures may be required after contamination with certain samples.
