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Chloramine (Mono)
Accuracy Check
Method Performance
Chloramine (Mono)
Page 4 of 6
To check test accuracy, prepare the following 4.5-mg/L (as Cl
standard fresh before use.
1. Add the contents of one Buffer Powder Pillow, pH 8.3, to about 50-mL of
organic-free water in a clean 100-mL Class A volumetric flask. Swirl to
dissolve the powder.
2. Using a Class A volumetric pipet, transfer 2.00 mL of Nitrogen, Ammonia
Standard Solution, 100-mg/L as NH
3. Dilute to volume with organic-free water, cap, and mix thoroughly. This is a
2.00-mg/L buffered ammonia standard.
4. Pipet 50.00 mL of the buffered ammonia standard into a clean 100-mL beaker.
Add a stir bar.
5. Obtain a recent lot of Chlorine Solution Ampules, 50–70 mg/L, and note the
actual free chlorine concentration for this lot.
6. Calculate the amount of Chlorine Solution to be added to the ammonia
standard using the following equation:
mL chlorine solution required
7. Open an ampule and, using a glass Mohr pipet, add the calculated amount of
Chlorine Solution slowly to the ammonia standard, while mixing at medium
speed on a stir-plate.
8. Allow the monochloramine solution to mix for 1 minute after all Chlorine
Solution is added.
9. Quantitatively transfer the monochloramine solution to a clean 100-mL
Class A volumetric flask. Dilute to the mark with organic-free water, cap, and
mix thoroughly. This is a nominal 4.5-mg/L (as Cl
standard.
10. Use this standard within 1 hour of preparation. Analyze according to the
High Range Monochloramine procedure described above.
11. To adjust the calibration curve using the reading obtained with the 4.5-mg/L
standard solution, touch
.
Standard Adjust
12. Touch
. Touch
On
Adjust
depends on the selected chemical form). If an alternate concentration is used,
touch the number in the box to enter the actual concentration, then touch
Touch
.
Adjust
Precision
Standard: 2.52 mg/L Cl
Program
66
See Section 3.4.3 Precision on page 42 for more information, or if the standard
concentration did not fall within the specified range.
–N into the flask.
3
455
=
--------------------------------------------------------------------- -
free chlorine concentration
on the current program menu. Touch
Options
to accept the displayed concentration (the value
2
95% Confidence Limits of Distribution
2.41–2.63 mg/L Cl
) monochloramine
2
) monochloramine
2
2
Chloramine (Mono)_MP_Low_MCF_Eng_2400.fm
.
OK
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