LaMotte SMART Spectro Spectrophotometer - Manual (Page 73)

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
NOTES: 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 is obtained.
To determine the percentage of Ammonia-Nitrogen that is unionized and ionized,
consult the Appendix.
AMMONIA-NITROGEN, High Range SMART Spectro Test Procedures 2.11
Test P
rocedures