LaMotte THPS in Tolcide® PS Biocides - Manual (Page 2)

PRO CE DURE
1.
Fill the test tube (0715) to the 25 mL line with the sample to be
tested.
2. For fresh water samples, use a 1 mL pipet (0354) to add 2.0 mL *DSP
Reagent, 10% Solution (4133). For saltwater samples, use another
1 mL pipet (0354) to add 2.0 mL *Borate Buffer Solution (4135).
3. Use another 1 mL pipet (0354) to add 2.0 mL of *PSSA Reagent, 5%
Solution (4134). Swirl to mix.
4. Add 6 drops of Starch Indicator Solution (4170WT). Swirl to mix.
5. Replace the regular cap on the bottle of *Iodine Solution, 0.025N
(6377) with the special dispenser cap (0601).
NOTE:
Replace the regular cap on the Iodine Solution 0.025N
bottle for storage.
6. Fill the Direct Reading Titrator (0381) with the *Iodine Solution,
0.025N (6377).
7. Slowly add *Iodine Solution, 0.025N (6377) to the test tube by
depressing the plunger. Swirl the test tube after each drop to mix
reagents.
8. Continue adding *Iodine Solution, 0.025N (6377) until 1 drop
results in a permanent blue/black color.
9. Read the concentration (in ppm) of THPS directly from the scale on
the Titrator.
NOTE: Take the titrator reading where the plunger meets the
titrator scale. Each small division is equal to 2 ppm.
10. Repeat Steps 1-9 on a blank (system water without biocide) to
determine background levels.
11. Subtract the blank reading from the reacted sample reading to
determine the concentration of THPS in the sample.
NOTE:
This test measures ppm active THPS. To obtain ppm of
formulation, divide ppm THPS by the activity (in percent) of the
formulation, and multiply by 100.
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