LaMotte SMART Spectro Spectrophotometer - Manual (Page 68)

PROCEDURE–FRESH WATER
Use universal sample holder.
1. Press and hold ON button until spectrophotometer turns on.
2. Scroll to and select PROGRAMMED TESTS from menu.
3. Scroll to and select ALL TESTS (or another sequence containing
3 Ammonia-N LF) from TESTING MENU.
4. Scroll to and select 3 Ammonia-N LF 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. Use the 1.0 mL plastic pipet (0354) to add 2.0 mL
of *Salicylate Ammonia #1 (3978). Cap and mix.
8. Use the 0.15 g spoon (0727) to add two measures of *Salicylate #2 Reagent
(7457). Cap and mix until dissolved. Wait 1 minute.
9. At end of 1 minute waiting period use 0.1 g spoon (0699) to add two measures
of *Salicylate #3 Reagent Powder (7458). Cap and shake vigorously for at
least 30 seconds and all solid has dissolved. Wait 12 minutes for maximum
color development.
10. At the end of 12 minute waiting period, mix, insert tube into chamber, close lid
and select SCAN SAMPLE. Record result.
11. Press OFF button to turn spectrophotometer off or press EXIT button to 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.
SMART Spectro Test Procedures 2.11 AMMONIA-NITROGEN, Low Range
Test P
rocedures