Cleaning and maintenance solutions

Electrodes must be handled with care. Each electrode must be completely cleaned and calibrated to the specified value before measurement. Handling, storage and maintenance have a significant impact on the accuracy and life of a pH electrode. Even minor phenomena such as air bubbles, crystallization, low electrolyte level, underflow of KCl electrolyte or contamination of the electrode can cause problems.

Immerse the electrode in a 3.8 to 4.0 molar KCl (sodium chloride) solution heated to 50°C for 1 hour. Cool the KCl solution to room temperature and rinse the electrode with deionized or distilled water. This procedure will remove contaminants from the reference electrode.

Signs indicating the need for electrode cleaning:

• long measurement stabilization time
• incorrect or unstable measurement
• calibration problems

Careful care will ensure faster response, improve measurement accuracy, and extend the life of the electrode. Regular maintenance of a pH electrode requires that the electrode be stored in the recommended storage solution between measurements and that the electrolyte of the refillable electrode be replenished before each measurement, if necessary. Never allow the electrode salt bridge to dry out.

The pH electrode requires periodic cleaning depending on the type of sample. The most suitable cleaning solution is one that selectively reacts with the contaminant. Then rinse the electrode thoroughly with distilled water and store in the recommended storage solution.