LaMotte DO 4000 Dissolved Oxygen Meter - Manual (Page 14)

SATURATED WATER USING A WINKLER TITRATION
The saturated water method using a Winkler titration to check the
oxygen level is limited by the accuracy the titration.
1. Fill a 1 liter beaker with distilled or deionized water. Adjust
temperature of the sample to approximately 25°C. Press the °C
button to turn the meter on. Record the temperature.
2. Aerate sample for 15 minutes.
NOTE: An aquarium pump or other bubbling equipment can be
used to aerate the sample.
3. Remove aerator from beaker. Determine dissolved oxygen level using
a Winkler Titration. Record reading. Repeat titration for a total of
three results. Use the average of the results as the dissolved oxygen
reading of the sample.
NOTE: LaMotte Company offers a dissolved oxygen kit using an
azide modification of the Winkler Titration. Order as code #7414 or
code #5860 (all liquid reagents).
4. Set “SALINITY COMP” and “SLOPE” knobs on meter to zero.
5. Keeping probe at an angle, slowly lower at least 3.5” into the aerated
sample. Tap the probe gently against the side of the beaker to
remove air bubbles. Press “°C” button. Stir sample continuously.
NOTE: If reading is unstable, stir more rapidly with probe.
6. Press “O
2
” button. Wait for reading to stabilize. Adjust the “slope”
knob until display reads concentration of the sample as determined
in Step 3.
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