This is a general-purpose, plastic bodied, single junction, gel-filled glass electrode, which is non-refillable. 

IMPORTANT: To maintain the level of the storage solution, the pH electrode’s glass membrane must be kept wet. 

Electrode Storage

Maintain the level of pH electrode storage solution, the pH sensitive membrane must be kept wet.

Store the electrode in equal volumes of pH 4.0 buffer and 3.5 - 4 mol dm-3 Potassium Chloride (KCl) solutions (1:1 v/v).

Never store the electrode in deionised or distilled water - this will cause migration of the electrode’s fill solution.

Recipe: Add 29 g of KCl to 100 cm3 of distilled water. Add 100 cm3 of a pH 4 buffer solution.

Please remember that to maintain the level of pH electrode storage solution, the glass membrane must be kept wet. 

Electrode Maintenance

The glass bulb can become coated with any compound that has an affinity for glass. After any cleaning procedure, soak the electrode in its storage solution for at least 30 minutes before use.

General cleaning procedure: - Soak the electrode in 0.1 mol dm-3 Hydrochloric acid (HCl) for between 10 to 30 minutes. Rinse thoroughly with distilled water. Soak in its storage solution for at least 2 hours before use. The pores of the reference junction may become clogged. If this happens, heat to 50 ̊C in 3 to 4 mol dm-3 Potassium Chloride (KCl), or pH 4 buffer solution for 1 hour, then allow to cool to room temperature in the same solution. Rinse with distilled water and soak in its storage solution for at least 30 minutes before use.

Inorganic coatings: - Soak in either 0.1 mol dm-3 Tetrasodium E.D.T.A acid solution or 1% Decon 90 solution for 1 – 2 hours.

Oil, Grease: - Carefully wash the electrode under warm tap water, using a non-filming dish washing detergent or stain removing prewash pre-treatment. Do not use automatic or electric dishwasher detergents. An overnight soak may be needed if build-up is heavy. Rinse thoroughly with fresh tap water, followed by 3 rinses of distilled water. Soak the electrode in its storage solution for at least 30 minutes before use.

Protein & Fatty Materials: - Either gently wipe the bulb with a tissue soaked in propanol, soak in 1% pepsin in 0.1 mol dm-3 hydrochloric acid (HCl) for at least 10 minutes or soak the pH electrode in contact lens enzymatic cleaner solution overnight. Rinse thoroughly with distilled water.

Highly resistant deposits: - Clean with H2O2 or sodium hyperchlorite.

Bacterial cultures: - Chemically sterilize with ethylene oxide, soak a cloth to wipe the entire body.

CAUTION - Do not use strong solvents such as halogenated hydrocarbons, petroleum ether, etc. for cleaning.