pH Meter - Electrode Requires Regular Maintenance
1. Calibration of electrodes
After the electrode is used for a period of time, the asymmetric potential and slope will change greatly, so it must be calibrated regularly.
The frequency of electrode calibration depends on the measured medium, electrode performance and accuracy requirements for measurement. Measurements with high precision requirements should be calibrated in time; general precision measurements can be used continuously for several weeks or even longer after one calibration. Calibration of the electrode is not necessary as often as the measurement display is accurate.
In addition, you can first test the standard solution that is closer to the measured solution, and then determine whether recalibration is required according to the size of the error. The prepared standard buffer solution can generally be stored for one week. If turbidity, mildew or precipitation is found, it should be disposed of properly and cannot be used any longer.
2. Storage of electrodes
If the pH electrode is not in use, the glass bulb must be placed in a humid environment. If the glass bulb is dehydrated, it will temporarily affect the performance of the electrode. The recommended storage steps are as follows:
Short-term: The electrodes are inserted into the LV potassium chloride solution. NOTE: Do not store in distilled water.
Long-term: Fill the protective bottle with fresh LV potassium chloride solution, and then insert the electrode. The O-ring of the protective bottle must seal in place and the cap must be hand-tight. NOTE: Do not store in distilled water.
Regeneration: When it is found that the electrode responds slowly and is almost dull, it should be soaked in a mixture of 10% HNO3 and NH4F (50g/l) to regenerate it. Usually within ten seconds.
3. Electrode cleaning
Cleaning of the pH electrode
Washing pH electrode glass bulb
Wash with a warm, neutral detergent solution. Brush the glass ball lightly with a soft brush, and then wipe it with a clean, soft cotton or cloth. Rinse thoroughly with distilled water, then soak in saturated LV potassium chloride solution for at least 30 minutes.
Inorganic pollution
Soak the glass bulb of the electrode in xi hydrochloric acid solution for a few minutes (note: only on the top of the glass bulb), then clean it with distilled water, and immerse it in LV potassium chloride solution for no less than 30 minutes.
Organic Grease Contamination
Try to clean it with a warm neutral detergent solution first, if you can’t meet the requirements, then clean the glass bulb with alcohol or acetone (note: only on the top of the glass bulb, not touching the diaphragm), and then immerse in LV potassium chloride solution , not less than 30 minutes.
ORP electrode cleaning
Inorganic pollution
Wash it with pure water, then soak it in LV potassium chloride solution for 6 hours before using it.
Organic oil pollution and oil film pollution
After cleaning the platinum surface with detergent, wash it with pure water, and then soak it in LV potassium chloride solution for 6 hours before using it.
Platinum surface is seriously polluted and forms an oxide film
Use toothpaste to polish the platinum surface, then wash it with pure water, and then soak it in LV potassium chloride solution for 6 hours before using it.
4. Electrode precautions
Do not dry or store the electrode in distilled water;
It is forbidden to scrub the electrode glass ball directly by hand, or scratch the glass ball with hard objects;
It is forbidden to reuse the standard solution;
If the glass electrode is cracked or damaged, it can no longer be used.
