LaMotte COD Plus Colorimeter 1922-EX2 - Manual (Page 62)

PROCEDURE
Use COD adapter (see p. 22).
1.
Homogenize sample if necessary.
2. Preheat COD heater block to 150±2°C.
3. Remove cap from COD tube vial. Hold vial at a 45° angle. Use a
volumetric pipet, to carefully add 2.0 mL sample water allowing the
sample to run down the side of the vial.
4. Cap and mix thoroughly.
5. Rinse the outside of the vial with distilled water. Wipe dry with a paper
towel.
6. Repeat steps 2 through 5 using 2.0 mL distilled water. This is the reagent
blank.
7. Place vials in preheated COD block heater and maintain temperature at
150±2°C for two hours.
8. At the end of the heating period turn the heater off. Wait 20 minutes for
the vials to cool to 120°C or less.
9. Remove vials from block heater. Invert several times to mix.
10. Allow to cool to room temperature.
11. Press and hold
ON button until colorimeter turns on.
12. Press ENTER to start.
13. Press ENTER to select TESTING MENU.
14. Select ALL TESTS (or a sequence containing 2 COD SR) from
PROGRAMMED TESTS menu.
15. Wipe the blank vial with a damp towel to remove fingerprints and
smudges. Wipe with a dry towel.
16. Scroll to and select 2 COD SR from menu.
17. Insert reagent blank tube into chamber. Align the center of the LaMotte
logo on the tube with the arrow shaped mark molded into the housing at
the front edge of the light chamber. Select SCAN BLANK.
18. Remove tube from colorimeter.
19. Insert digested water sample tube into chamber. Position the tube as
instructed above. Select SCAN SAMPLE. Record result. For the most
accurate results, take three readings on each sample and average the
results.
20. Press
OFF
button to turn colorimeter off or press
EXIT
button to exit to
a previous menu or make another menu selection.
COD PLUS TEST PROCEDURES 2/04 COD - STANDARD RANGE 3/4