pH electrodes

Electrodes are delicate measuring instruments that require special care and handling to produce accur

Product Description

Electrodes are delicate measuring instruments that require special care and handling to produce accurate results. The lifespan of an electrode can be prolonged through regular calibration and cleaning (please see pH Calibration & Maintenance Kit for more information.) However, an electrode does have a limited life span, in the same way that a battery does. It’s a good idea to keep a spare on hand. Symptoms of an aging electrode include sluggish and erratic readings.

Below are a few remedies you can try before replacing the electrode:

Unblocking Reference Junction:

A blocked or clogged reference junction is the cause of about 80% of all pH measurement difficulties, causing slow response, off-scale readings and noisy readings. You can try one of the following:
  • Gel-filled electrodes: Soak the electrode in warm water (about 60C) for 5 – 10 minutes. Or place the electrode in warm saturated KCl solution (60C) and allow both electrode and solution to cool down to room temperature.
  • Liquid filled electrodes: Sleeve and annular junction – drain the electrode, rinse the cavity with distilled water and refill it with fresh electrolyte. For sleeve-type electrodes, rotate the sleeve to re-establish flow if necessary.
  • Ceramic Junction:
For Calomel types only: Soak the electrode in water for about 10 minutes, and check for electrolyte flow. Alternatively, soak the electrode tip in concentrated HCl for 5 – 10 minutes (use adequate ventilation and safety measures when doing this). Rinse, then check for electrolyte flow again.
For Silver / Silver Chloride Types only: Soak the electrolyte in warm saturated KCl solution (60C) for about 10 minutes, and check for electrolyte flow. Alternatively, soak the electrode tip in concentrated ammonium hydroxide for 5 – 10 minutes (use adequate ventilation and safety measures). Rinse the electrode, then check for electrolyte flow.
For Ceramic Junctions only: if the junction remains clogged, gently sand the junction area (be careful not to touch the glass bulb), and check for electrolyte flow.

Cleaning Glass pH Membrane:

Dirty glass membranes are usually indicated by beads of water forming on the bulb when rinsing with distilled water. The bulb can be cleaned as follows:
  • Protein: Soak in fresh protein removal solution ECDPCBT for 30 minutes, rinse thoroughly before use.
  • For Inorganic deposits: Wash with EDTA, ammonia or acids.
  • For Grease and Similar Films: Wash with acetone, methanol, etc.

Reconditioning Glass membrane:

Prolonged use, excessive alkaline immersion or high temperature operation will case surface leaching of the membrane glass. Dip the electrode tip into 0.1N HCl for less than 5 minutes, then rinse with water. Then dip in 0.1N KOH for 5 minutes, and rinse thoroughly with water. If the problem persists, repeat the steps but note that frequent HCl / KOH treatment can shorten the electrode life.

Handling of Electrodes:

  • Always keep pH electrode moist when not in use for a period of time – store in a beaker containing Electrode Storage Solution. For long term storage, store in storage bottle with Electrode Storage Solution.
  • NEVER store in deionised water or in distilled water. The ions will leach out causing a slow response.
  • The Electrode should be rinsed thoroughly with distilled or deionised water between measurements and calibrations. Blot the electrode dry with lint free paper towel to gently dislodge excess water. Don’t rub the electrode or it will become electrostatically charged.
  • Never use polymer or plastic body electrodes in samples containing organic solvents.
  • For refillable electrolytes, the filling solution should be filled up to, but not past, the refill hole. Make sure that the refill hole is open when measuring.

1. Glass or Plastic Body?

Glass body better for corrosive materials or solvents.Withstands temperature above100°C, more accurate and is easier to clean, but breaks more easily. Plastic is ideal for field use and more rugged applications.

2. Single or Double Junction?

Economical single junction electrodes are suitable for general-purpose applications. Double junction ideal for biological samples, solutions that contain sulfides, heavy metals or Tris.

3. Refillable or Sealed Design?

The refillable design has a hole for replenishment and can be used many times. The Sealed design has no refill hole, the reference electrolyte is usually a gel. It requires less maintenance, but replacement of the electrode is necessary when it gets contaminated. It has slightly lower accuracy and a shorter life.

4. General Use or Specialty Use?

Electrodes for general purpose are economical and usually measure 120mm (length) by 12 mm (diameter). They usually have a 1m cable and a BNC connector.There are many different specialty electrodes.

Top Selling Electrodes:

General use:

  • X-YU-PH201MS pH Electrode: General purpose, plastic body, single junction, gel filled pH Electrode. Measures 1 – 13 pH at a temperature range of 0 to 80C. Ideal for out-in-the-field or rugged applications.
  • X-YU-PH210g pH Electrode: General purpose, glass body, single annular ceramic reference junction. Measures 1 – 13 pH and has a temperature range of 0 – 100C. Suitable for general purpose, aqueous pH measurements. Quality control, general laboratory and aquarium water.
  • ECFG7379201B pH Electrode: General purpose, glass body, double junction electrode. Measures 0 – 13 pH and has a temperature range of 0 – 110C for high temperature measurements, reference contamination problems that require a double junction reference, such as media containing sulphides, bromides, iodides and cyanides.

Specialty Use:

  • pH Spear / Spear tip are specifically designed for measuring solid and semi-solid samples such as cheese, meat, fruit, bread or other similar samples.
  • Open pore electrode for samples high in proteins, creams, fats and cosmetics.
  • pH Electrode for high viscosity solutions such as emulsions, suspensions, paints and varnishes where frequent cleaning is necessary.
  • pH Electrode for measuring the pH of soil.
  • pH and ORP (Oxygen Reduction Potential) Electrodes that also judge how much oxidation or reduction takes place under existing conditions. Useful in the treatments of industrial wastes, study of biological systems, oxidation of cyanide, bleaching of pulp, manufacture of bleach and reduction of chromate wastes.

When all else fails, choose the right replacement Electrode:

There are a number of criteria to be considered when choosing electrodes. There are many different shapes and sizes and materials available that will fit with any pH meter (a BNC connection being the most common).

If in doubt, send us an email enquiry and we will recommend the best electrode for your application – there may be a specialty electrode that is better suited to your application that you are not aware of.

In your enquiry, describe your pH meter, the tests you do, the temperature at which you test and whether you do them in a lab or in the field. We would like to recommend the pH electrode best suited to your purpose.

Additional Information

Weight 0.00 kg