Hach DR2400 - Page 214

Chlorine, Total
Chlorine, Total
Page 6 of 10
ChlorineTot_PT2_ULow_DPD_Eng_Ody.fm
Interferences
13. When the timer
beeps, introduce the
contents of the cylinder
into the Pour-Thru Cell.
When the flow stops,
touch
Read. Results will
appear in µg/L Cl
2
.
14. Use this value to
correct the sample result
obtained in this
procedure.
15. Flush the Pour-Thru
Cell with at least 50 mL of
deionized water
immediately after use.
Interfering Substance Interference Levels and Treatments
Bromine, Br
2
Interferes at all levels
Chlorine Dioxide, ClO
2
Interferes at all levels
Chloramines, organic May interfere
Copper, Cu
2+
Greater than 1000 µg/L
Iodine, I
2
Interferes at all levels
Manganese, Oxidized (Mn
4+
,
Mn
7+
) or Chromium,
Oxidized (Cr
6+
)
1. Adjust sample pH to 6–7.
2. Add 6 drops Potassium Iodide (Cat. No. 343-32) (30-g/L) to a 50-mL sample.
3. Mix and wait 3 minutes.
4. Add 6 drops Sodium Arsenite* (Cat. No. 1047-32) (5-g/L) and mix.
5. Analyze the treated sample as described in the procedure.
6. Subtract the result from this test from the original analysis to obtain the correct
chlorine concentration.
* Samples treated with sodium arsenite for manganese or chromium interferences will be hazardous wastes as regulated by the
Federal RCRA for arsenic (D004). See Section 4 for more information on proper disposal of these materials.
Nitrite, NO
2
–
Ozone, O
3
Interferes at all levels
Peroxides May interfere
Extreme sample pH or highly
buffered samples
Adjust to pH 6–7. See Section 3.3 Interferences on page 41.
NEFILL LINE
mg/L nitrite Apparent µg/L chlorine
2.0 mg/L 3 µg/L
5.0 mg/L 5 µg/L
10.0 mg/L 7 µg/L
15.0 mg/L 16 µg/L
20.0 mg/L 18 µg/L