Looking after your electrodes

Electrode Calibration

Since glass pH electrodes measure H concentration relative to their half cells, they must be calibrated periodically to ensure accurate, repeatable measurements. Our wide selection  of calibration buffers include solutions standardised against NIST certified pH references for calibrating meters with resolution up to 0.001pH.

Although calibration against one reference buffer typically ensures accurate pH measurement, frequent 2 point or 3 point calibrations ensures the most reliable results.Make sure your pH system has includes 4, 7, and 10 pH buffers.

Conditioning

Our pH electrodes are shipped with the electrode tip wet. Before using the electrode for the first time follow these 3 steps to condition your electrode:

  1. Remove the protective cap from the bottom of the sensor and rinse the electrode with distilled or deionised water. ( Do not wipe the electrode with any tissue.)
  2. Place the electrode in a beaker containing one of the following solutions listed. 3.8M or 4.0M KCL, or  4.0pH buffer  Soak for 20 mins. NOTE never condition an electrode in distilled water long term exposure to pure water will damage the the specil glass membrane.
  3. After conditioning the electrode for 20 mins, rinse the electrode in distilled or deionised water. The electrode is now ready for calibration and measuring pH.

Handling

Electrodes should be rinsed between samples with distilled or deionised water. Never wipe an electrode with tissues wiping can cause erroneous readings due to static charges. Blot the end of the probe with lint free paper to remove excess water.

Refilling electrodes

The filling solution in refillable electrodes should be filled up to, but not past the refill hole.  Make sure the refill hole is left slightly open when measuring so that the fill solution flows properly through the reference junction.

Storage

Always keep you pH electrode moist. We recommend 4M Kcl for long term storage, and for normal everyday use we recommend pH4 buffer. DO NOT store electrodes in distilled or deionised water this will cause ions to leach out of the glass bulb and render your electrode useless.

After storage you may notice some white KcL crystals forming outside the electrode, this will not interfere with measurements.  Simply rinse the electrode and blot dry before use.