LaMotte PHOSPHONATE TEST KIT FI-DB - Manual (Page 4)

PRO CE DURE
For most accurate results, a blank test should be run on a sample of the
water containing no phosphonate. Any result from this blank test
should be subtracted from the result recorded in Step 6.
1.
Fill test tube (0970-S) to 10 mL line with sample water.
2. Add 1 drop of Sodium Thiosulfate, 0.1N (6155) and 5 drops of
*Fluoride Inhibitor (3929). Cap and mix.
3. Use 0.1g spoon (0699) to add one level measure of Xylenol Orange
Reagent Powder (6165). Swirl until dissolved.
4. Adjust pH between 2.5 and 3.0. Dip a strip of pH paper (2958)
into sample. Match color to a color standard on the side of the roll.
Add *Hydrochloric Acid, 1.0N (6130) drop by drop, checking pH
after each drop, until color matches 2.8 color standard. Solution
will be yellow.
5. Fill pipet (0371) with *Thorium Nitrate Solution (6158PS). While
gently swirling the tube, add *Thorium Nitrate Solution drop by
drop until color changes from yellow to pink. Count number of
drops added. Hold pipet vertically.
6. Multiply the number of drops used in Step 5 by the conversion
factor from the chart. Record as ppm Phosphonate.
Phosphonate Compound Name Factor
Dequest 2000 AMP(NTP) 0.8
Dequest 2006 NaAMP 1.0
Dequest 2010 HEDP(A) 0.6
Belcor 575 0.5
NOTE: If any other phosphonate compound is used, the factor
must be determined experimentally using standard solutions of that
compound.
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12/01