1—63
Chlorine Dioxide, continued
4. Repeat the chlorine dioxide test on the chlorine standard, including the Glycine
addition. The reading should be less than 0.10 mg/L ClO
2
. This verifies that the
Glycine is eliminating free chlorine interference.
Standard Solution Method
Standard solutions for chlorine dioxide are difficult and time-consuming to prepare.
Errors can occur if attention to detail is not addressed during preparation of the
standards. Hach prepares the calibration curve under rigorous analytical laboratory
conditions. Hach recommends using the factory calibration.
A user calibration or a user-prepared chlorine dioxide standard may be required by a
regulatory official or agency. Two options are available on the Pocket Colorimeter II to
meet this requirement.
A chlorine dioxide standard may be prepared and used to validate the calibration curve
using the Standard Calibration Adjust feature (see Standard Calibration Adjust on
page 2—13). The concentration of the prepared standard must be determined with an
alternate instrument such as a spectrophotometer, colorimeter, amperometric titration
or by using another alternate method. The concentration of the chlorine dioxide
standard must be between 2.00 and 4.50 mg/L chlorine dioxide.
To Next Page
Loading...
