- 12 -
P5 — Restore to factory default setting (No—Yes)
1. Press , “No” flashes, press to select No to Yes, press
to confirm; The meter returns to measurement mode.
2. If not selecting “Yes”, press to return to measurement mode.
5.7
pH Electrode’s Maintenance
5.7.1 Daily maintenance
The soaking solution contained in the supplied protective bottle is used to maintain activation in the glass bulb
and junction. Loosen the cap, take out the electrode and rinse in distilled or water before taking a measurement.
Insert the electrode and tighten the cap after measurements to prevent the solution from leaking. If the soaking
solution is cloudy or moldy, replace the 3M KCL solution.
* We DO NOT recommend using other brand’s soaking solution, since different chemicals can be used
and potential damage can be caused to the electrode
)
* The electrode should
NOT
be soaked and stored in
purified or distilled
water, protein solution, acid fluoride
solution, or organic lipids. Distilled water or purified water is only recommended for rinsing electrodes.
5.7.2 Calibration buffer solution
For calibration accuracy, the pH of the standard buffer solution must be reliable. The buffer solution should be
refreshed often, especially after heavy use. We recommend 10-15 times of use before replacing the pH buffers.
5.7.3 Protect glass bulb
The sensitive glass bulb at the front of the combination electrode should not come in contact with hard surfaces.
Scratches or cracks on the electrode will cause inaccurate readings. Before and after each measurement, the
electrode should be rinsed with distilled water or purified water. If a sample sticks to the electrode or it’s
contaminated, the electrode should be thoroughly cleaned using a soft brush with soap water and then rinsed
with distilled water. After that, soak it in the KCL solution again for at least 6 hours.
5.7.4 Renew glass bulb
Electrodes that have been used over a long period of time will become aged. Submerge the electrode in
0.1mol/L hydrochloric acid 24 hours, then rinse the electrode in distilled water, then submerge it in KCL soaking
solution for 24 hours.
The method to prepare 0.1mol/L hydrochloric acid: dilute 9mL hydrochloric acid in distilled water to 1000mL.
For serious passivation, submerge the bulb in 4% HF (hydrofluoric acid) for 3-5 seconds, and wash it in
distilled water, then submerge it in the soaking solution for 24 hours to renew it.
5.7.5 Clean contaminated glass bulb and junction (please refer to Table-8)
Table-8 Clean contaminated glass bulb and junction
Contamination
Cleaning Solutions
Inorganic metal oxide
Dilute acid less than 1mol/L
Organic lipid
Dilute detergent (weak alkaline)
