LaMotte SMART Spectro Spectrophotometer - Manual (Page 76)

PROCEDURE–FREE CHLORINE
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
17 Cl DPD-Liq
) from TESTING MENU.
4. Scroll to and select 17 Cl DPD-Liq from menu.
5. Rinse a tube (0290) with sample water. Fill to the 10 mL line with sample.
6. Insert the tube into chamber, close lid and select SCAN BLANK.
7. Remove the tube from spectrophotometer.
8. Add 5 drops of DPD 1A Free Chlorine Reagent (P-6740).
9. Add 5 drops of *DPD 1B Free Chlorine Reagent (P-6741). Cap and mix.
10. Insert tube into chamber, close lid and select SCAN SAMPLE. Record
result as ppm free chlorine.
PROCEDURE–TOTAL CHLORINE
11. Add 5 drops of *DPD 3 Total Chlorine Reagent (P-6741). Cap and mix.
þNOTE: For wastewater samples, Standard Methods for the Examination of
Water and Wastewater recommends waiting 2 minutes for full color
development.
12. Insert tube into chamber, close lid and select SCAN SAMPLE. Record
result as ppm total chlorine.
13. Subtract the Free Chlorine reading from the Total Chlorine reading to
determine ppm combined chlorine.
14. Press
OFF button to turn the spectrophotometer off or press EXIT button
to exit to a previous menu or make another menu selection.
þNOTE: 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.
SMART SPECTRO TEST PROCEDURES 05.04 Chlorine - Liquid DPD 3/3