Hach CM130, User Manual

Page: 74 / 112

Interferences
The substances that are shown in Table 15 interfere in the chlorine (Cl
2
) determination at the given
concentrations.
Table 16 shows the substances that were tested and do not interfere at or below the levels that are
shown.
Table 15 Interfering substances
Interfering substance Interference level
Bromine, Br
2
Positive interference at all levels
29
Bromate, BrO
3
-
Positive interference at all levels
29
Chlorine Dioxide, ClO
2
Positive interference at all levels
29
Chloramines, organic Positive interference at all levels
29
Chloride salts – combined in solution:
• Calcium – 200 mg/L as Ca
2+
• Magnesium – 200 mg/L as Mg
2+
• Potassium – 200 mg/L as K
+
• Sodium – 400 mg/L as Na
+
• Chloride – 300 mg/L as Cl
-
Maximum negative interference of 0.007 mg/L at 0.10 mg/L as Cl
2
Chlorate and Chlorite, ClO
3
-
& ClO
2
-
Positive interference at all levels
29
Chromium, oxidized (Cr
6+
) Positive interference at all levels
29
Iodine, I
2
Positive interference at all levels
29
Manganese, oxidized (Mn
4+
, Mn
7+
, MnO
4
-
) Positive interference at all levels
29
Ozone, O
3
Positive interference at all levels
29
Peroxides Positive interference at all levels
29
Sulfate – 250 mg/L as SO
4
2-
Maximum negative interference of 0.007 mg/L at 0.10 mg/L as Cl
2
Highly buffered samples or extreme pH Can prevent the correct pH adjustment of the sample by the
reagents. Highly buffered water and water that is not within the EPA
Secondary Drinking Water Standard range of pH 6.5 to 8.5 can
cause interference.
Table 16 Non-interfering substances
Substance Maximum level tested Substance Maximum level tested
Alkalinity (as CaCO
3
) 500 mg/L Fluoride (F
-
) 4 mg/L
Aluminum (Al
3+
) 0.2 mg/L Hardness (as CaCO
3
) 1000 mg/L
Antimony (Sb) 0.006 mg/L Iron, ferric (Fe
3+
) 0.3 mg/L
Arsenic (As) 0.01 mg/L Lead (Pb
2+
) 0.015 mg/L
Barium (Ba
2+
) 2.0 mg/L Mercury (Hg
2+
) 0.002 mg/L
Beryllium (Be
2+
) 0.004 mg/L Nitrate (NO
3
-
) 10 mg/L
Cadmium (Cd
2+
) 0.005 mg/L Selenium (Se
4+
) 0.18 mg/L
Calcium (Ca
2+
) 400 mg/L as Ca Silver (Ag
+
) 0.1 mg/L
29
This substance is an oxidant and can be thought of as the analyte. The result can be thought of
as a total oxidant concentration shown in units of total chlorine.
72 English