Chlorite, "Quick" Two Step Amperometric Titration - Hach AutoCAT 9000 Instruction Manual

Titration Workstation
Scope and Application:
*Procedure equivalent to Standard Methods 4500-CI0
Sample Tips and Techniques
• Soak all glassware in a strong chlorine dioxide (ClO
Rinse thoroughly with deionized water. Use the glassware for this method only.
• Remove sample portions with a volumetric pipet. Always place the tip at the bottom of the sample container. If using 200-mL sample
increments, use a 100-mL pipet to withdraw two portions of sample.
• Always use organic-free water for sample dilution. (Cat. No. 26415-49).
• Rinse the electrode, temperature probe, and anti-diffusion tip with deionized water before every titration.
.
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.
Instrument Tips and Techniques
• Adjust the contrast of the display by accessing the Methods menu and pressing 7 to lighten or 0 to darken.
• A distinction is drawn between running a new test and a new sample. Each test is a replicate run of the current or previous sample analysis.
The AutoCAT 9000 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.
• 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.
• Press STOP at any time to interrupt instrument operation; the user can resume, restart, or quit completely.
• Press the CHECK MARK at any time during data acquisition to halt data collection.
• Press DEL during any timer period (except Start Timer) to immediately exit the timer and proceed to the next step.
• Press ESC during any titration/calibration data collection period or timer to access Edition mode. See Edition Mode on page 30.
• 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.
• A distinction is drawn between running a new Test and a new Sample. Each Test is a replicate run of the current or previous.
50081_Chlorite.fm
For water and wastewater*.
E.
2
) or chlorite (CIO
2
"Quick" Two Step Amperometric Titration
–
) solution (300–500 mg/L) for at least 1 hour.
2
Chlorite
0.1–5.0 mg/L as ClO
Chlorite
Page 127
–
2