Hach AutoCAT 9000 - Page 76

Chlorine Dioxide Generator Yield
Chlorine Dioxide Generator Yield
Page 74
50081_ChlorineDioxideGeneratorYield.fm
1. Press the CHECK MARK
to enter a new volume.
Press
1 to confirm.
2. Transfer 200 mL of
organic-free DI water to a
Gas Washing Bottle (GWB).
Add identical volume of
sample pipetted in Titration
1, Step 4.
Add 1 dose of pH 7.0
phosphate buffer, and swirl
to mix.
3. Insert the purge tube
and dispersion tip into the
GWB. Connect the GWB
inlet to a tank of purified
nitrogen.
4. Use a needle valve
to adjust the flow of
nitrogen to provide a steady
stream of bubbles through
the sample.
Press the
CHECK MARK
to continue.
5. Purge nitrogen gas
through the sample for
15 minutes.
When the timer beeps,
transfer the purged sample
into a 250-mL beaker. Add
the magnetic stir bar.
Note: If the nitrogen purge has
already been performed, press
DEL to skip this timer and
proceed to the next step.
6. Use the measuring
spoon to add 1.0 g of
potassium iodide (KI).
Place the sample onto the
stirrer platform.
Press the
CHECK MARK
to confirm.
Note: KI is added in excess.
The precise amount added is
not crucial for the accuracy or
precision of the analysis.
7. The timer will begin,
allowing the reagents to mix
before starting the titration.
8. Lower the electrode
head onto the beaker rim.
Press the
CHECK MARK
to confirm.
AutoCAT Titration Method ClO
2
Yield Titration 3