Hach DR/850 Procedures Manual page 229

Nitrogen, Free Ammonia and Chloramine (Mono), continued
Note: The sample for
Monochloramine
measurement does not need
pretreatment.
Accuracy Check (Monochloramine, Program 110)
Substance
Aluminum
Chloride
Copper
Iron
Manganese
Nitrate
Nitrite
Phosphate
Silica
Sulfate
Zinc
Samples containing high levels of both Total Hardness and
Alkalinity may become turbid (cloudy) after the addition of the
Free Ammonia Reagent Solution. If this occurs by the end of the
first reaction period, the sample for Free Ammonia measurement
must be pretreated as follows:
1. Measure 10 mL of sample into the cell for Free Ammonia
measurement.
2. Add the contents of one Hardness Treatment Reagent Powder
Pillow (Cat. No. 28823-46) to the sample.
3. Cap the cell and invert until the reagent is dissolved.
4. Remove the cap.
Continue with the analysis at step 2 using the pretreated sample
as the Free Ammonia cell.
1. Prepare the following monochloramine standard fresh before
use.
2. 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.
3. Using a Class A volumetric pipet, transfer 2.00 mL of
Nitrogen, Ammonia Standard Solution, 100 mg/L as NH
into the flask.
229
Level Tested
0.2 mg/L Al
1200 mg/L Cl
1 mg/L Cu
0.3 mg/L Fe
0.05 mg/L Mn
10 mg/L NO –N
3
1 mg/L NO –N
2
2 mg/L –PO
4
100 mg/L SiO
2
1600 ppm as CaCO
3
5 ppm Zn
–N
3