Common troubleshooting methods for online pH meters
1. Aging of glass electrodes
Phenomenon: Response lag; Sensitivity decreases; Zero drift.
Handling:
(1) Regularly perform electrode calibration.
⑵ Electrode activation: The aged electrode can be immersed in a mixed solution of 1M acetic acid and 1M potassium chloride (1:1), activated for 10 minutes, and then removed for cleaning. Electrodes with less severe aging can be activated by soaking them in distilled water or 0.1N dilute hydrochloric acid solution for 24 hours.
2. Glass electrode contamination
Phenomenon: Decreased sensitivity; Measurement deviation.
Handling:
The alkaline precipitate on the electrode can be cleaned in a dilute hydrochloric acid solution, and then the electrode can be cleaned with distilled water.
The grease attached to the electrode can be cleaned with hot water and household detergent, or wiped with gauze.
⑶ Colloidal dirt can be cleaned with a strong hydrochloric acid solution. After washing, be sure to clean the electrode with distilled water.
After cleaning with acid, alkaline or organic solvents, the electrode should be soaked in distilled water for a period of time to restore the damaged hydration layer.
3. Reference electrode contamination (ceramic plug blockage)
Phenomenon: The measured value is too high; The indication is unstable.
Treatment: Can be cleaned with hot water and household detergent; Oil or alkaline pollutants can be cleaned with organic solvents (such as alcohol) or dilute hydrochloric acid solution; If the pollution is severe, it can be brushed with a soft bristled brush or wiped with filter paper strips. For non flow electrodes, the electrode can be placed in an 80 ℃ electrolyte until the electrolyte cools down.
4. Reference electrode poisoning
Phenomenon: Error indication; Unstable indication; Unable to calibrate.
Treatment: If only the electrolyte inside the reference electrode is contaminated, replace the electrolyte; If the non flow electrode or inner electrode is poisoned, the electrode needs to be replaced.
5. Signal cable to ground impedance reduction (<107 Ω)
Phenomenon: unstable and jumping indications; Display out of range, unable to measure.
Handling: Replace the cable, dry the cable plug or junction box with a hair dryer.
