LaMotte SMART Spectro Spectrophotometer - Manual (Page 102)

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-6743). Cap and mix.
NOTE: 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.
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.
SMART Spectro Test Procedures 2.11 CHLORINE, DPD Liquid
Test P
rocedures