PASCO PS-2169 Water Quality MultiMeasure Sensor - Manual (Page 7)

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M o d e l N o . P S - 2 1 6 9 D i s s o l v e d O x y g e n
7
DO
2
Calibration
Perform a one-point calibration using 100% humidified air as the known standard,
which is equivalent to 100% saturated (pure) water. Prepare 100% humidified air as
follows:
1. Place about 5 mL (to a height of about 1 cm) of deionized water into a clean elec-
trode storage bottle.
2. Slip the cap and O-ring of the soaker bottle over the end of the probe. Insert the
probe into the soaker bottle and screw on the cap. Adjust the height of the end of
the probe to about 2 cm above the water.
3. Shake the probe and bottle vigorously for about 10 seconds. Shake off any large
water drops from the membrane.
4. Hold the probe vertically so that it is in the air above the water, not in the water
itself.
5. Perform a one-point calibration on either the Dissolved Oxygen (%) or Dis-
solved Oxygen (mg/L) measurement. If you are calibrating the percentage mea-
surement, enter “100” as the known value. If you are calibrating the mg/L
measurement, look up the known concentration in Appendix D. For instructions
on calibrating in DataStudio, see Appendix A. For instructions on calibrating on
the Xplorer GLX, refer to the Xplorer GLX Users’ Guide.
Measuring DO
2
Follow the instructions above to fill the probe with electrolyte solution and calibrate
the measurement. Start data collection. Remove the storage bottle from the probe.
Immerse the end of the probe in the solution to be measured. Gently swirl the probe or
stir the solution to prevent localized oxygen depletion at the probe end. Wait for the
reading to stabilize. Rinse the electrode with deionized water before measuring a dif-
ferent solution.
DO
2
Probe Maintenance and Storage
The probe comes with extra filling solution, a replacement membrane cartridge and
O-ring, and a plunger for installing the cartridge. Order the Electrode Maintenance
Kit (CI-6541) to replace these items.
Electrode Cleaning
To maintain optimal performance, periodically clean the silver electrode and replace
the electrolyte filling solution as follows:
1. Unscrew and remove the cartridge housing at the end of the probe. Discard the
old filling solution from the cartridge housing.
Shake
vigorously
Electrode
storage bottle
Water level
Probe tip
Preparation of 100%
humidified air for
calibration
Syringe
Plunger Replacement
O-ring
Replacement
membrane cartridge
Filling
Solution
Remove loose silver oxide
from cathode