TM 10-6630-245-13&P
2.6.8.14. Nitrogen Ammonia Test.
a.
Purpose of Test: To determine the total amount of nitrogen present in a water sample in the form of ammonia.
b.
Range: 0.0 to 2.0 mg/l
c.
Equipment Used: Found in Main Carrying Case, para 1.8, fig. 1-1 and in Zinc Test Kit, para 2.6.5, fig. 2-11
Volumetric pipet, 1.0 ml, (5), fig. 1-1
Rochelle salt solution, (13), fig. 1-1
Nessler reagent, (17), fig. 1-1
Spectrophotometer, (20), fig. 1-1
Pipet filler, (27), fig. 1-1
Graduated cylinder, (31), fig. 1-1
Deionized water, (8), fig. 2-11
d.
General Techniques Used: Refer to paragraphs cited below as required by procedure.
Planning the Test, para 2.6.1.1
Cleaning Glassware, para 2.6.1.2
Handling and Storing Reagents, para 2.6.1.3
Collecting Water Samples, para 2.6.1.4
Mixing, para 2.6.1.5
Using Graduated Cylinders, para 2.6.1.6
Using Pipets, para 2.6.1.7
Spectrophotometer, para 2.6.2.2
e.
Test Procedure:
WARNING
High voltage used with Spectrophotometer. Misuse can cause electrical shock and damage
equipment. When operating with 115V or 220V power, make sure the power source and
equipment are in ground potential. Ensure that the power cable connections are correct for the
desired voltage power before connecting the power source.
NOTE
For best results, the temperature of the deionized water and the water sample should be 68 ± 2°F
(20 ± 1°C). Higher temperatures will cause high readings. Lower temperatures will cause low
readings.
(1)
Refer to para 2.6.2 for set up and operation of the Spectrophotometer.
(2)
Fill one spectrophotometer sample cell(7, fig. 2-5) with 25 ml of sample water. Use the graduated
cylinder(3 1, fig. I1-1) to collect and measure the water. This will be the test sample.
(3)
Use a clean graduated cylinder(31) to measure 25 ml of deionized water(8, fig. 2-11). Pour into the other
spectrophotometer sample cell(7, fig. 2-5). This will be the "blank cell."
WARNING
ROCHELLE SALT SOLUTION
May be harmful if swallowed. May be irritating to skin or eyes. Do not ingest or allow contact with skin or eyes. In case
of contact, immediately flush eyes and skin with plenty of water. In case of ingestion, give large quantities of water. Call
medic.
(4)
If the water being tested has a hardness greater than 100 mg/l, add one drop of Rochelle salt solution(l3,
fig. 1-1) to both sample cells(7, fig. 2-5). Otherwise, the hard water will cause an incorrectly high result.
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