YSI 5239 Dissolved Oxygen Probe - Manual (Page 8)

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titration. Choose the one which best fits your application.
Calibration in air is the simplest and most accurate method of
calibration.
•
For air calibration, place the probe in air at 100% relative
humidity. To achieve this, place the probe in the plastic
calibration bottle (provided) with a wet sponge or paper
towel in the bottom.
•
For air-saturated water calibration, air-saturate a
volume of water (300 to 500 ml) by aerating for at least 15
minutes at a relatively constant temperature. Place the
probe in the aerated water and provide adequate stirring (at
least 1 foot per second) while calibrating.
•
To calibrate to a Winkler-titrated sample, determine the
dissolved oxygen value of a sample by Winkler titration.
Place the probe in the sample and provide adequate stirring
(at least 1 foot per second) while calibrating.
YSI recommends that the following procedure to calibrate the
5239 probe:
1. Connect the 5239 probe to one of the YSI 50 series DO
meters.
2. Turn on the meter and wait for the probe to polarize
and the reading to stabilize. Depending on the
condition of the probe, the time for stabilization could
vary between 15 and 30 minutes. For a new probe with
clean electrodes and a properly installed membrane
cap, it usually takes 15 to 20 minutes. If the electrodes
are fouled or the membrane or electrolyte are not in
good condition, it may take longer to stabilize than
anticipated.