Iodine, Amperometric Back Titrant Calibration - Hach AutoCAT 9000 Instruction Manual

Titration Workstation
Scope and Application:
0.0282 N (28.2 mN) Iodine Standard Solution titrant.
Sample Tips and Techniques
• Sample glassware must be cleaned and pretreated to satisfy any chlorine demand. See Section 7.2 Container Pretreatment on
page 63 for additional information.
• Always use organic-free reagent water for sample dilution (Cat. No. 26415-49).
• Rinse the electrode, temperature probe, and anti-diffusion tip with deionized water before every calibration.
Reagent Tips and Techniques
• Download the "Certificate of Analysis" (COA) to obtain the exact concentration of any unopened bottle of Hach titrant or standard
solution. See Obtaining the Certificate of Analysis for Hach Reagents on page 41.
• Hach buffer reagents for chlorine titrations are highly recommended for this analysis.
• Never substitute buffers designed for calibrating pH meters. They may contain dyes that interfere with amperometric titration.
• Never use buffers contaminated with mold or bacteria.
• It is recommended that titrations for titrant calibration be performed in triplicate.
Instrument Tips and Techniques
• Adjust the contrast of the display by accessing the Methods menu and pressing 7 to lighten, and 0 to darken.
• A distinction is drawn between running a new test and a new sample on the AutoCAT. Each test is a replicate run of the current or
previous sample analysis. The AutoCAT automatically tracks the results of a series of tests, and automatically calculates the
mean and standard deviation for all the results. Each test is given a different number, all of which are listed under the same
Sample ID. When starting a new sample, a new ID is assigned.
• Rinse the electrode, temperature probe, and anti-diffusion tip with deionized water between calibrations.
• The AutoCAT 9000 can accommodate any sample size. Standard Methods recommends a default volume of 200 mL. The
volume can be adjusted to expand the test range.
• The AutoCAT 9000 calculates concentration based on the sample volume. Make sure that the sample volume is correct.
• The data for any sample calibration may be analyzed repeatedly in manual or automatic mode. The results are not stored in the
archives until they are accepted.
• Press the STOP key any time to interrupt instrument operation. The user will be given the option to resume, restart,
or quit.
• Press the CHECK MARK key any time during data acquisition to halt data collection.
• Press the DEL key during any timer period (except the Start Timer) to immediately exit the timer and proceed to the next step in
the procedure.
• Flush the burette each day before the first sample test or calibration is performed. See Daily Start-up on page 26.
• Flush the burette when changing titrants. See Changing Titrants on page 25.
50081_IodineCalibration.fm
The following sequence guides the user through the calibration procedure for the
Amperometric Back Titrant Calibration
Iodine
Iodine
Page 57