Hach DR/850 Procedures Manual page 152

CHLORINE DIOXIDE,
Method Performance
Interfering Substance
Acidity
Alkalinity
Bromine, Br
2
Chlorine, Cl
2
Chloramines, organic
Flocculating agents
Hardness
continued
Precision
Program Standard
112 0.24 mg/L
112 4.79 mg/L
113 0.26 mg/L
113 4.83 mg/L
For more information on determining precision data and method
detection limits, see Section 1 of the DR/800 Procedures Manual.
Estimated Detection Limit (EDL)
Program
112
113
For more information on derivation and use of Hach's estimated
detection limit, see Section 1 of the DR/800 Procedures Manual.
Interferences
A substance interferes if it changes the final reading by 0.1 mg/L
ClO or more.
2
Interference Levels and Treatments
Greater than 150 mg/L CaCO
instantly. Neutralize to pH 6–7 with 1 N sodium hydroxide. Determine amount to be
added on separate sample aliquot, then add the same amount to the sample being tested.
Correct for volume addition (see Section 1, Correction For Volume Additions, in the
DR/800 Procedures Manual).
Greater than 250 mg/L CaCO
instantly. Neutralize to pH 6–7 with 1 N sulfuric acid. Determine amount to be added
on separate sample aliquot, then add the same amount to the sample being tested. Correct
for volume addition (see Section 1, Correction For Volume Additions, in the DR/800
Procedures Manual).
Interferes at all levels.
May interfere at levels greater than 6 mg/L. Additional glycine may be able to
compensate for this interference.
May interfere.
High levels of most flocculating agents can be tolerated. This tolerance is decreased
if chlorine is present. See the information about metals in this table. In the presence
of 0.6 mg/L Cl , Al(SO )
2 4
No effect at less than 1,000 mg/L as CaCO
95% Confidence Limits
0.22–0.26 mg/L ClO
4.67–4.91 mg/L ClO
0.21–0.27 mg/L ClO
4.71–4.97 mg/L ClO
EDL
0.04 mg/L ClO
0.04 mg/L ClO
. May not develop full color or color may fade
3
. May not develop full color or color may fade
3
(< 500 mg/L) and FeCl
3 2
3
.
152
2
2
2
2
2
2
(<200 mg/L) may be tolerated.