Frequently Asked Questions About pH Electrodes
1. How long is the service life of the pH electrode?
The lifespan of a properly used and maintained pH electrode is expected to be around one to three years. Factors that lead to a shortened electrode life include: high temperatures and measuring at extreme pH conditions, even for well-maintained electrodes. If electrode performance begins to degrade, the pH-sensitive glass membrane can be regenerated and the electrode performance can be restored to previous levels.
2. How to choose the correct pH electrode?
To ensure the best 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 vessel dimensions (length and width limitations). Electrode selection is particularly important for non-aqueous, low-conductivity, protein-rich and viscous measurement media, where general purpose glass electrodes are susceptible to many different influences leading to measurement errors. The response time and accuracy of an electrode depends on many factors. Measurements made at extreme pH and temperature or low conductivity have longer response times than measurements made at room temperature on neutral pH aqueous values.
3. How to maintain/clean the electrodes?
Routine maintenance is important to prolong the life of your pH electrode. When the liquid level is likely to be lower than the liquid level of the sample solution, it is necessary to fill the electrolyte-fillable electrode with electrolyte. Maintenance prevents sample backflow into the electrode. The entire reference electrolyte should also be replaced periodically (approximately once a month). This ensures that the electrolyte is fresh and does not crystallize during the measurement due to evaporation from the open filling spout. It is important to ensure that no air bubbles develop inside the electrode, especially near the junction. If this happens, the measurement results will become unstable. To remove air bubbles, gently shake the electrode in a similar way to shaking a thermometer.
To clean the electrode, rinse it with deionized water after each measurement, but never wipe it with a paper towel. The paper towel surface has the potential to scratch and damage the pH-sensitive glass membrane, wipe off the gel layer, and create a static charge on the electrode. Such electrostatic charges can cause the measurement signal to become very unstable. Special cleaning procedures may be required after contamination with certain samples.
