LaMotte COD Plus Colorimeter 1922-EX2 - Manual (Page 123)

PROCEDURE
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 27 Tannin) from
TESTING MENU
.
5. Scroll to and select 27 Tannin from menu.
6. Rinse a clean tube (0290) with sample water. Fill to the 10 mL line with
sample.
7. Insert tube into chamber, close lid and select SCAN BLANK.
8. Remove tube from colorimeter. Use the plain pipet (0352) to add 4 drops
of *Tannin Reagent #1 (7833). Cap and mix.
9. Use the 1.0 mL pipet (0354) to add 2.0 mL of *Tannin Reagent #2
(7834). Cap and mix. Wait 30 minutes for full color development.
10. At end of 30 minute waiting period, mix, insert tube into chamber, close
lid and select SCAN SAMPLE. Record result.
11. Press
OFF button to turn colorimeter off or press EXIT button to exit to a
previous menu or make another menu selection.
NOTES:
l 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.
l For the most accurate results, the sample and reagents should be at
20±2°C.
TANNIN 2/2 COD PLUS TEST PROCEDURES 6/02