pH electrode lifespan depends on the amount of use, temperature of sample, types of sample, and the care and maintenance of the probe.
pH Electrode Lifespan
Hanna pH electrodes have a 6 month warranty. With proper care and maintenance, pH electrodes typically last 1 to 2 years. Some types of samples may benefit from specialized electrode design in order to get the maximum lifespan from your pH electrode. Samples such as soil, food, and chemically aggressive samples can all benefit from specialized electrodes.
Testing High Temperature Samples
Elevated temperatures reduce the lifespan of pH electrodes. At room temperature (25˚C), a pH electrode will typically last 1 to 2 years. A general rule of thumb is that for every 25˚C increase, the electrode life of a general purpose pH electrode will decrease by half.
If you're measuring samples at temperatures greater than 50˚C, use a pH electrode with high temperature (HT) glass to prolong electrode lifespan, such as in the HI1043.
Storing a pH Electrode
Proper pH Electrode Storage
Store your pH electrode in storage solution to keep the pH glass hydrated, and tointernal electrolyte concentration. For more steps, click on the following link to our other article, What should I store my pH electrode in? .
Purified water (DI) will cause an osmotic effect on the internal reference solution, and will decrease the electrode life. If you're using a refillable electrode, replace the fill solution. If you're using a gel-filled electrode, the electrode will have to be replaced.
Storing the pH Electrode Dry
The hydrated glass layer on pH electrodes is delicate. The hydration is key to accurate measurements. While the electrode can be restored by rehydrating the electrode in the HI70300L storage solution. However, even with rehydration, response and accuracy can be compromised.
Cleaning the Electrode
Proper pH Electrode Cleaning
Cleaning your pH electrode properly is paramount as the most common cause for inaccurate measurments is a dirty electrode. Always rinse your electrode prior to and after readings (or calibrations) with deionized or distilled water. If you still have residue on your pH electrode, use a cleaning solution to help remove it. A general purpose cleaning solution such as the HI7061L is great, but if you need something a bit more specific, we have you covered. There are cleaning solutions available for a wide range of samples including ones for protein, inorganics, grease and fats, and more. When using a cleaning solution there are a few key steps to follow.
- Rinse the pH electrode with deionized or distilled water.
- Soak the pH electrode in your chosen cleaning solution for at least 15 minutes.
- Rinse the pH electrode one more time with deionized or distilled water.
- Then, submerge the pH electrode in storage solution such as HI70300L for at least 1 hour to rehydrate the probe.
Hanna Tip: Make sure to always rehydrate your pH electrode after using a cleaning solution. While the cleaning solution helps to dissipate contaminants on the pH sensing glass, it also strips away moisture. Rehydration of the pH glass is key to getting an accurate calibration and readings post-cleaning.
Wiping the pH Electrode
Again, remember that the pH sensing glass on the electrode is delicate. Wiping the glass tip can result in you stripping away layers of the hydrated glass causing irreparable damage to the electrode. If you have stubborn gunk stuck to your electrode use application specific cleaning solutions.
Solutions that have hydrofluoric (HF) acid in them will dissolve the electrode glass. Use electrodes with HF resistant glass. The HI1143B will resist HF up to 2 g/L at a pH of 2, at temperatures less than 60˚C.