TEST INSTRUCTIONS - Geotech Environmental Equipment

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 3 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 another sequence containing 25 COD LR)from
PROGRAMMED TESTS menu.
15. Scroll to and select 25 COD LR from menu.
16. Wipe the blank vial with a damp towel to remove fingerprints and
smudges. Wipe with a dry towel.
17. Insert reagent blank tube into chamber. Select SCAN BLANK.
18. Remove tube from colorimeter.
19. Insert digested water sample tube into chamber. 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.
Smart2 TEST PROCEDURES 03.05 COD-LR 3/4