LaMotte COD Plus Colorimeter 1922-EX2 - Manual (Page 114)

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 23 Silica Lo)
from TESTING MENU.
5. Scroll to and select 23 Silica Lo 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. (See Note)
8. Remove tube from colorimeter. Add 6 drops *Silica Reagent #1 (V-4466).
Cap and invert to mix.
9. Add 12 drops of *Silica Reagent #2 (V-4467). Cap and mix. Wait 5
minutes.
10. Add 8 drops of *Silica Reagent #3 (V-4468). Cap and mix. Wait 2
minutes.
11. Use the 0.1 g spoon (0699) to add one measure of *Silica Reagent #4
(V-6284). Cap and mix gently until powder has dissolved. Wait 5 minutes
for full color development.
12. At end of 5 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.
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.
COD PLUS TEST PROCEDURES 6/02 SILICA - LOW RANGE 3/3