LaMotte DPD-FAS TITRIMETRIC OUT FIT DT User Manual
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II. SIMPLIFIED PROCEDURE FOR FREE, COMBINED &
TOTAL CHLORINE AND NITROGEN TRICHLORIDE
A. FREE CHLORINE
1.
Use the 0.5 g spoon (0698) to add 0.5 g of *DPD #1 Powder (6807)
to the 250 mL Erlenmeyer flask (0433).
2.
Fill the 100 mL graduated cylinder (0419) to the 100 mL line with
sample water. Pour into Erlenmeyer flask. Swirl until powder is
dissolved. If Free Available Chlorine is present, solution will turn
pink.
NOTE:
In the presence of high monochloramine, add 10 drops of
*Steadifac Reagent (6383WT) to prevent interference. This will
give a Free Chlorine reading only. Discard and start again at Step
1A and continue to Step B5 for monochloramine, etc. Do not add
*Steadifac Reagent if other forms of chlorine are to be determined.
3.
Titrate rapidly with the diluted Ferrous Ammonium Sulfate Solution
in the buret until the pink color disappears. Record buret reading as
Reading A.
Reading A (mL) = (ppm) Free Chlorine
Retain sample and buret for testing Monochloramine.
B. TOTAL CHLORINE
4.
Use the 0.5 g spoon (0698) to add 0.5 g of *DPD #1 Powder (6807)
to a clean 250 mL Erlenmeyer flask (0433).
5.
Use the 1.0 g spoon (0697) to add 1.0 g of *Potassium Iodide
Crystals (6809) to the flask (0433).
6.
Use the 100 mL graduated cylinder (0419) to add 100 mL of sample
water to the flask (0433). Swirl until reagents are dissolved. Wait 2
minutes. If Total Chlorine is present, solution will turn pink.
7.
Titrate rapidly with the diluted Ferrous Ammonium Sulfate Solution
in the buret until the pink color disappears. Record buret reading as
Reading B.
Reading B (mL) = (ppm) Total Chlorine
C. COMBINED CHLORINE
Reading B – Reading A = (ppm) Combined Chlorine
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