LaMotte SMART 2 - Manual (Page 191)

PROCEDURE
þ NOTE: Place Dispenser Cap (0692) on *Mixed Acid Reagent (V-6278). Save
this cap for refill reagents.
1. Press and hold ON button until colorimeter turns on.
2. Press ENTER to start.
3. Press ENTER to select TESTING MENU.
4. Select ALL TESTS (or another sequence containing 64 Nitrate-N
LR
) from TESTING MENU.
5. Scroll to and select 64 Nitrate-N LR from menu.
6. Rinse a clean tube (0290) with sample water. Fill to 10 mL line with
sample.
7. Insert tube into chamber, close lid and select SCAN BLANK.
8. Remove tube from colorimeter and pour off 5 mL into graduated cylinder
or similar. Discard the remaining sample.
9. Pour the 5mL sample from a graduated cylinder or similar into the tube.
Use the graduated cylinder or similar to measure 5 mL of *Mixed Acid
Reagent (V-6278) and add to tube. Cap and mix. Wait 2 minutes before
proceeding to Step 10.
10. Use the 0.1 g spoon (0699) to add two measures of *Nitrate Reducing
Reagent (V-6279). Cap.
11. Hold tube by index finger and thumb and mix by inverting approximately
50-60 times a minute for four minutes. Wait 10 minutes for maximum
color development.
þ NOTE: At end of waiting period an undissolved portion of Nitrate
Reducing Reagent may remain in bottom of the tube without affecting
results.
12. At the end of the 10 minute waiting period, mix, insert tube into
chamber, close lid and select SCAN SAMPLE. Record result.
13. Press
OFF button to turn colorimeter off or press EXIT button to exit to a
previous menu or make another menu selection.
þ NOTE: For 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 convert Nitrate Nitrogen (NO
3
–N) results to ppm Nitrate (NO
3
), multiply
by 4.4.
Smart2 TEST PROCEDURES 1.07 Nitrate-Nitrogen–LR 3/3