Hach DR/700 - Page 607

61-51
Method 10045
NITROGEN, MONOCHLORAMINE AND
FREE AMMONIA
(0 to 0.55 mg/L NH
2
Cl-N or NH
3
-N)
Salicylate Method For drinking water
1. Install module
number
61.01
in a DR/700.
Note: The DR/700 must
be calibrated before
sample analysis. See
Calibration following
these steps.
2. Press: I/O
The display will show
610 nm
and module number
61.01
After 2 seconds, the
display will show a
program number, the
concentration units
and the zero prompt.
3. Press the
PROGRAM key once
or twice until the
lower display shows
program number
61.000
If necessary, press the
UP ARROW until the
upper display shows
0.00 mg/l
4. Fill three 10-mL
round sample cells to
the 10-mL line with
sample.
Note: For proof of
accuracy, use a
0.50 mg/L NH
3
-N
solution (preparation
given in Accuracy
Check) in place of the
sample.
5. Label the three
cells "blank", "free
ammonia", and
"monochloramine".
Cap the cell labeled
"blank".
Note: Free ammonia is
the ammonia and
ammonium in the
sample, corrected for
monochloramine.
6. To test for free
ammonia, add one
drop of Hypochlorite
Solution to the cell
labeled free
ammonia. Cap the
cell and mix.
Note: Occasionally
shake the Hypochlorite
Solution bottle to ensure
proper dispensation.