Best Practices on caring for your pH testers
This tutorial is from our friends at Hanna Instruments, taken from their 'pH Best Practices guide'.
Keep the electrode hydrated
Why — Drying out the electrode leads to drifting pH values, slow response times, and incorrect measurements.
Fix — “Revive” a dry electrode by submerging the bulb and junction in pH storage solution for at least one hour.
Rinse, do not wipe your electrode
Why — Wiping the pH glass can produce a static charge which interferes with the pH reading of the electrode.
Fix — Simply rinse the electrode with distilled or deionized water (DI). Blot (do not rub) with a lint-free paper towel (e.g. Kimwipes®) to remove excess moisture.
Store your electrode in storage solution
Why — Storing in deionized water (DI) causes ions to leach from the glass membrane and reference electrolyte resulting in a slow and sluggish response.
Fix — Store your electrode in storage solution or pH 4.01 or pH 7.01 buffer if you do not have storage solution.
Clean your electrode regularly
Why — Deposits can form on the electrode during use, coating the sensing glass. This can lead to erroneous calibrations and readings.
Fix — Clean the electrode using a specially formulated cleaning solution for pH electrodes, ideally one that’s developed for your application.
Why — All pH electrodes need to be calibrated often for best accuracy.
Fix — The frequency of calibration depends on how accurate you want to be - daily calibration is ideal.
Pick the right electrode for your sample
Why — General purpose electrodes are functional for a wide variety of applications but not ideal for all samples.
Fix — Based on your sample you may require an electrode designed for food, high/low temp, non-aqueous, or other types of samples.
Properly submerge your electrode
Why — Both the pH sensing glass and reference junction need to be completely immersed in order to function properly.
Fix — Add enough sample to submerge both the junction and sensing glass.
Inspect your electrode
Why — Over time, the sensing portion of the glass becomes less responsive and will eventually fail. Damage from use is also possible. This will cause erroneous readings.
Fix — Check your electrode for damage and perform a slope and offset calculation. Reference blog for instructions.