LaMotte PHOSPHONATE TEST KIT OP-DC User Manual
Page 3
PRO CE DURE
1.
Fill the test tube (0970-S) to the 10 mL line with sample water.
2.
Add 1 drop of Sodium Thiosulfate (6155).
3.
Add the exact number of drops of *Hydrochloric Acid (6130)
recorded in Step D.
4.
Use the 0.1 g measuring spoon (0699) to add one level measure of
Xylenol Orange Powder (6165). Swirl to dissolve. The solution will
turn yellow.
5.
Use the pipet assembly (0371) to add Thorium Nitrate (6158PS)
one drop at a time, mixing after each drop, until the sample color
changes to pink. Be sure to hold the pipet in a vertical position to
form uniformly sized drops.
6.
Record the number of drops required to obtain the endpoint color
change.
7.
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 above.
8.
This test has been calibrated for Dequest 2006. When a different
compound is to be tested, the amount of Thorium Nitrate added
should be multiplied by a conversion factor to determine 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.