LaMotte COD3 Plus, Operator'S Manual

Page: 82 / 119

Nickel
COD3 Plus Colorimeter 10.16
PROCEDURE
1. Use the 10 mL graduated cylinder (0416) to measure 10 mL of sample water. Pour
into glass test tube (0608).
2. Use the 1 mL pipet (0354) to add 1 mL of *Hydrochloric Acid, 2.5N (6251).
3. Use the 0.1 g spoon (0699) to add 2 measures of *Ammonium Persulfate Reagent
(6566). Add two drops of *Silver Nitrate Solution, 0.0141N (6346WT). Mix until the
powder has dissolved. The solution will be slightly cloudy at this point.
4. Use 10 mL graduated cylinder (0416) to add 5 mL of Sodium Citrate, 10%
(6253).
5. Use a second 1 mL pipet (0354) to add 1 mL of *Ammonium Hydroxide, Conc.
(6537). Mix, then dilute to 25 mL with deionized water.
6. Use a third 1 mL pipet (0354) to add 1 mL of *Dimethylglyoxime, 1% (6254). Mix.
Wait 20 minutes for color development.
7. At end of 20 minute waiting period fi ll a clean tube (0290) to the 10 mL line with the
developed test sample.
8. Fill a second clean tube (0290) to 10 mL line with deionized water or untreated
sample water. This is the blank.
9. Press and hold until colorimeter turns on.
10. Press
ENTER
to select Testing Menu .
11. Select All Tests (or another sequence containing 064 Nickel ) from Testing Menu .
12. Scroll to and select 064 Nickel from menu.
13. Insert the blank into chamber, close lid and select Scan Blank .
14. Insert test sample into chamber, close lid and select Scan Sample . Record
result.
15. Press to turn colorimeter off or press EXIT to exit to a previous menu or
make another menu selection.
NOTE: It is strongly suggested that a reagent blank 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.
Testing