LaMotte SMART Spectro Spectrophotometer - Manual (Page 63)

PROCEDURE
Use universal sample holder.
1. Press and hold
ON button until spectrophotometer turns on.
2. Scroll to and select PROGRAMMED TESTS.
3. Scroll to and select ALL TESTS (or another sequence containing
5 Ammonia-N H
) from TESTING MENU.
4. Scroll to and select 5 Ammonia-N H from menu.
5. Rinse a clean tube (0290) with sample water. Fill to the 10 mL line with
sample.
6. Insert tube into chamber, close lid and select SCAN BLANK. (See Note)
7. Remove tube from Spectro. Add 8 drops of Ammonia Nitrogen Reagent
#1 (V-4797). Cap and mix. Wait 1 minute.
8. Use the 1.0 mL pipet (0354) to add 1.0 mL of *Ammonia Nitrogen
Reagent #2 (V-4798). Cap and mix. Allow 5 minutes for maximum color
development.
9. At end of 5 minute waiting period, mix, insert tube into chamber, close lid
and select SCAN SAMPLE. Record result.
10. Press
OFF button to turn the spectrophotometer off or press the EXIT
button exit to a previous menu or make another menu selection.
CALCULATIONS:
To express results as Unionized Ammonia (NH
3
):
ppm Unionized Ammonia (NH
3
) =
ppm Ammonia-Nitrogen (NH
3
–N) x 1.2
To express results as Ionized Ammonia (NH
4
):
ppm Ionized Ammonia (NH
4+
) =
ppm Ammonia-Nitrogen (NH
3
–N) x 1.3
þNOTES: For the best possible results, a reagent blank should be determined
to account for any contribution to the test result by the reagent system. To
determine the reagent blank, follow the above test procedure to scan a
distilled or deionized water blank. Then follow the above procedure to
perform the test on a distilled or deionized water sample. This test result is
the reagent blank. Subtract the reagent blank from all subsequent test results
of unknown samples. It is necessary to determine the reagent blank only
when a new lot number of reagents are obtained.
To determine the percentage of Ammonia-Nitrogen that is unionized and
ionized, consult the Appendix.
Ammonia-Nitrogen–HR 2/2 SMART SPECTRO TEST PROCEDURES 05.04