Method Performance; Interferences - Hach Pocket Colorimeter II Instruction Manuals

Chlorine Dioxide,
In addition, a user-generated calibration curve can be made and programmed into the
Pocket Colorimeter™ II. See

Method Performance

Typical Precision (95% confidence interval):
4.78 ± 0.22 mg/L ClO
2.08 ± 0.04 mg/L ClO
Estimated Detection Limit:
EDL = 0.04 mg/L ClO

Interferences

Samples containing more than 250 mg/L alkalinity or 150 mg/L acidity as CaCO
inhibit full color development, or the color may fade instantly. Neutralize these
samples to pH 6–7 with 1 N Sulfuric Acid Standard Solution or 1 N Sodium Hydroxide
Standard Solution. Determine the amount required on a separate 10-mL sample. Add
the same amount to the sample to be tested. Correct for the additional volume.
continued
User-Entered Calibration on page
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