Hach AutoCAT 9000 - Page 103

Total Chlorine
Total Ch lo rine
50081_Chlorine_Total_Back.fm Page 101
9. Add 1 SwifTest
dispensation (0.1 g) of
potassium iodide (KI).
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.
10. Add 1.0 mL of pH 4
acetate buffer.
Press the
CHECK MARK
to confirm.
Note: Acetate buffer is added
to adjust the sample pH. The
amount used is not crucial for
the accuracy or precision of
the analysis.
11. The timer will start and
the reagents will mix for a
short period of time before
titration begins.
12. Lower the electrode
head onto the beaker rim.
Press the
CHECK MARK
to confirm.
13. The analysis parameters
that have been stored for the
current Sub-ID may be
edited at this time.
Highlight the appropriate
line and press the
CHECK MARK to change one
of the analysis parameters or
press
1 to confirm.
Note: Any changes made will
become the new default
parameters for this method
Sub-ID.
Note: These Sub-ID
parameters can be edited here
as 'run-time' settings, or from
the Main Menu as described in
Section 3.5.
Note: This step will be skipped
if autoscaling software is
enabled.
14. The Start Timer will
begin to allow the electrode
to stabilize before data
collection.
After the electrode has
stabilized, the AutoCAT will
begin data acquisition and
plot the titration curve.
15. The Zoom Range
Determination window will
display the titration curve.
Use the navigation keys to
select and move the cursors
(vertical lines) to define the
range of data points for
analysis.
Proceed to step 16.
Note: Defining the range of
data points allows the user to
eliminate undesirable portions
of the titration curve from the
analysis.
16. Select the type of end
point determination.
Press the
CHECK MARK for
Automatic and proceed to
step 19 or press
DEL for
Manual.
Note: Automatic determination
attempts to identify linear
segments without user input.
Note: This screen is not
displayed if the Auto-detection
software is enabled.