Hach DR/850, Procedures Manual, Page: 225 / 460

225
Nitrogen, Free Ammonia and Chloramine (Mono)
Method 10200
Indophenol Method
*
(0–4.50 mg/L Cl
2
and 0–0.50 mg/L NH
3
–N)
For finished chloraminated drinking water
Note:
For the most accurate chloramine results, determine a reagent
blank for each new lot of reagent using deionized water instead of
sample. Subtract the blank value from the final chloramine result.
* U.S. Patent 6,315,950
1.
Enter the user
program number for
monochloramine.
Press:
PRGM
The display will show:
PRGM?
2.
Press:
110 ENTER
The display will show
mg/L Cl
2
and the zero icon.
Note: For alternate forms,
press the
CONC
key.
3.
Fill two cells with
10 mL of sample
Label one cell “Free
Ammonia” and one cell
“Monochloramine”.
4.
Place the
Monochloramine cell
into the instrument so
that the cell tab is at the
two-o’clock position.
Make sure the sample
cell tab is completely
seated in the cell holder
slot.
Tightly cover the sample
cell with the instrument
cap.
5.
Press:
ZERO
The cursor will move to
the right, then the
display will show:
0.00 mg/L Cl
2
Remove the cell from
the instrument.
6.
Add the contents of
one pillow of
Monochlor F to the cell
for the Monochloramine
measurement.
7.
Cap the cell and
shake for 20 seconds to
dissolve the reagent.
A green color will form
if monochloramine is
present.
8.
Add one drop of
Free Ammonia Reagent
Solution to the cell for
Free Ammonia
measurement.
FA M
Tab
Slot
M
M
10
mL
5
mL
M
FA