L mott – LaMotte AMMONIA NITROGEN TEST KIT NANR User Manual
Page 2
USE OF THE OCTET COM PARA TOR
The Octet Comparator contains eight permanent
color standards. A test sample is inserted into the
openings in the top of the comparator. The sample
can then be compared to four color standards at once,
and the value read off the comparator. For optimum
color comparison, the comparator should be
positioned between the operator and a light source, so
that the light enters through the special light-diffusing
screen in the back of the comparator. Avoid viewing
the comparator against direct sunlight or an irregularly
lighted background.
PART 1 - PRO CE DURE
1.
Rinse a test tube (0843) with sample water. Fill to 10 mL line with
sample water.
2.
Add 8 drops of Ammonia Nitrogen Reagent #1 (4797). Cap and mix.
Wait 1 minute.
NOTE:
When testing salt (sea) water, increase the amount of
Ammonia Nitrogen Reagent #1 to 20 drops.
3.
Use the pipet (0354) to add 1 mL of *Ammonia Nitrogen Reagent #2
(4798). Cap and mix. Wait five minutes. Remove cap.
NOTE:
When testing salt water, the reading must be made in one
minute to avoid interference from a precipitate which may form.
4.
Insert the sample tube into the Axial Reader (2070). Match sample
color to a color standard. Record as ppm Total Ammonia Nitrogen.
To express results as Unionized Ammonia (NH
3
):
ppm Ammonia Nitrogen (NH
3
–N) x 1.2 = Ammonia (NH
4
)
To express resluts as Ionized Ammonium (NH
4
+
):
ppm Ammonia Nitrogen (NH
3
–N) x 1.3 = Ammonium (NH
4
+
)
5.
If the color of the test sample is darker than the highest color
standard, repeat the test on a sample diluted 1 to 1 with
ammonia-free or distilled water. Multiply the reading by a factor of 2.
PART 2 - CON VER SIONS
Ammonia in water occurs in two forms: toxic unionized ammonia (NH
3
), and
the relatively non-toxic ionized form, ammonium ion (NH
4
+
). This test
method measures both forms as ammonia-nitrogen (NH
4
+
–N) to give the
total ammonia-nitrogen concentration in water. The actual proportion of
each compound depends on temperature, salinity, and pH. A greater
L Mott