LaMotte SMART Spectro Spectrophotometer - Manual (Page 207)

ERYTHORBIC ACID PROCEDURE
Use universal sample holder
1. Press and hold ON button until spectrophotometer turns on.
2. Scroll to and select PROGRAMMED TESTS.
3. Scroll to and select ALL TESTS (or another sequence containing
40 E-thorbic A) from TESTING MENU.
4. Scroll to and select 40 E-thorbic A from menu.
5. Rinse a tube (0290) with sample water. Fill to 10 mL with sample.
6. Insert the tube into chamber, close lid and select SCAN BLANK.
7. Remove the tube from spectrophotometer.
8. Add 3 drops of *DEHA Reagent #1 (4791). Swirl to mix.
9. Add 3 drops of *DEHA Reagent #2 (4792). Swirl to mix.
10. Add 3 drops of *DEHA Reagent #3 (4793). Invert 3 times to mix.
11. Insert the tube into chamber. Close lid.
12. Wait 15 minutes. Do not open the lid during the waiting time. The reaction is
photosensitive.
13. Remove tube from chamber. Invert 2 times to mix.
14. Immediately insert tube into chamber, close lid and select SCAN SAMPLE.
Read within 30 seconds. Record result in ppm erythorbic acid.
15. Press OFF button to turn the spectrophotometer 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 is obtained.
OXYGEN SCAVENGERS SMART Spectro Test Procedures 2.11
Test P
rocedures