Hanna Instruments HI 904, Uick Start Manual, Page: 11 / 180

11
QUICK START GUIDE
Fill Titration Vessel with Reagent
The titration vessel must be filled with reagent up to the MIN marker (about 75 mL):
• Lower the reagent tube below the liquid level inside the reagent bottle.
• From the Idle screen, press .
• Push and hold the FILL button located on the top of the air pump.
• Wait until the vessel is filled up to the MIN marker with solvent.
• Stop the air pump by pressing and then confirm the approximate amount of
reagent in the vessel.
• Raise the reagent tube above the liquid in the reagent bottle.
Prepare the Reagent for Samples
Before beginning a titration, residual moisture inside the titration vessel and reagent must be
reacted:
• From the Idle screen, press . The titrator will enter Pre-Titration mode, start the
magnetic stirrer, and begin dosing in the titration vessel.
• Once all residual moisture has been reacted (endpoint potential is reached), the
titrator will enter Drift Analysis mode (assuming Automatic Drift Entry is selected).
The titrator calculates the rate of atmospheric moisture seeping into the titration
beaker for the next minute and displays the result in the lower right corner of the
display.
• If the Drift Rate is stable and the endpoint potential is maintained, the titrator will
enter Standby mode. The titrator continues to maintain the endpoint potential and
update the background drift rate.
Note : New (or cleaned) detector electrodes have low electrical resistance due to a lack of
platinum-iodine complexes on the electrode surface. This may cause initial mV readings to
be low and prevent proper pre-titration of the reagent. The endpoint value (100 mV by
default) should be 200-250 mV below the mV value of “wet” reagent for proper pre-titration
to occur. If necessary, adjust the endpoint and/or imposed current (in Method Options) to
facilitate proper pre-titration. The platinum-iodine complex should form after several titrations
and raise the mV readings.
Preparing and Introducing the Sample
Sample Mass Preparation
Measuring the sample size by mass using an analytical balance will give the most reproducible
results.