L A B W A R E
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5. For higher measurement accuracy, the instruments should be calibrated by a standard
buffer solution. The used standard buffer solution should be discarded after several times
used.
6. Keep the instrument clean and dry, especially the socket of the electrode in the meter.
Use the cotton and anhydrous ethanol to clean these sockets and dry them.
7. Wash the electrode bulb with DI water before and after the measurements. Dry it with
filter paper,
8. (a) The glass bulb condemnation or aging: immerse the electrode in 0.1 mol/L HCl
solution (9 ml concentrated HCL solution is diluted with DI water to 1000 ml) for 24
hours, wash it with DI water. Then immerse it in the 3 mol/L KCl solution for another
24 hours to active it. Or immerse the glass bulb in 4 % HF solution for 3 – 5 seconds,
wash it with DI water, then immerse the glass bulb in 3 mol/L KCl solution for 24
hours to active it.
(b) Cleaning of the glass bulb and pollution: (for reference)
condemnation
Cleaner
Inorganic metal oxide
diluted acid (<1 mol/L)
Organic grease
Diluted detergent (weak alkaline)
Polymer resin
Diluted alcohol, acetone, ethyl ether
Protein cell sediment
Acid enzyme solution (yeast tablets)
Pigment substance
Diluted bleach, peroxide
9. One year is the lifetime of an electrode usage. The lifetime will be shorter if the electrode
is used in the harsh conditions or maintenance improperly. The aged or failed electrode
should be replaced with new one for good measurement result.
10. Unplug the power supply after the meter is switched off. Don’t unplug the power supply
code when the meter is on.
