Interferences - VOLTCRAFT CLB-600 Bedienungsanleitung

13. Interferences

Interfering Substance
Acidity
Alkalinity
Bromine, Br
2
Iodine, I
2
Chlorine Dioxide, ClO
Chloramines, organic
Hardness
Manganese, Oxidized
(Mn , Mn ) or
4+ 7+
Chromium Oxidized
(Cr ),
6+
Interference Level
More than 150 mg/L CaCO
the color may fade instantly. Adjust to pH 6–7 with 1 N Sodium
Hydroxide. Measure the amount to add on a separate sample
aliquot, then add the same amount to the sample that is tested.
Correct the test result for the dilution from the volume addition.
More than 250 mg/L CaCO
the color may fade instantly. Adjust to pH 6–7 with 1 N Sulfuric
Acid. Measure the amount to add on a separate sample aliquot,
then add the same amount to the sample that is tested. Correct
the test result for the dilution from the volume addition.
Positive interference at all levels
Positive interference at all levels
Positive interference at all levels
2
May interfere.
No effect at less than 1000 mg/L as CaCO
Pre-treat the sample as follows:
1 Adjust the sample pH to 6–7.
2 Add 3 drops of Potassium Iodide (30-g/L) to 10 mL of sample.
3 Mix and wait 1 minute.
4 Add 3 drops of Sodium Arsenite (5-g/L) and mix.
5 Use the test procedure to measure the concentration of the
treated sample.
6 Subtract this result from the result without the treatment to
obtain the correct chlorine concentration.
. The full color may not develop or
3
. The full color may not develop or
3
3
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