LaMotte TDS-DR 4801-DR - Manual (Page 2)

PRO CE DURE
PART A
1. Fill a test tube (0778) to 10 mL line with sample water.
2. Add 3 drops *Methyl Orange Indicator, 0.1% w/Halidex (2299). Cap and
mix. Solution will turn yellow.
3. Fill a Direct Reading Titrator (0384) with *TDS Reagent A (4802DR).
Insert Titrator into the center hole of the test tube cap.
4. While gently swirling the test tube, slowly press the Titrator plunger to
dispense *TDS Reagent A until the yellow color changes to pink. Read the
test result directly from the scale where the large ring on the Titrator meets
the Titrator barrel. Record as Result A. Discard the test sample and any
TDS Reagent A remaining in the Titrator.
PART B
In the second part of the TDS test, the sample water is passed through an ion
exchange column, which exchanges the various cations (Na, Ca, Mg, etc.) for
hydrogen ions, which are then titrated with *TDS Reagent B. Two ready-to-use
resin columns are furnished in this kit. Each column may be used for twenty
water samples before being discarded. Keep a record of the number of times a
column is used.
5. Suspend a resin column (1079) in the second test tube (0778) by inserting
the tip of the column into the center hole of the test tube cap.
6. Add a small amount of Demineralized Water (3 or 4 mL) to the resin
column.
7. Use the 1.0 mL pipet (0354) to add 5 mL of sample water to the column.
8. When all of this water has passed through the column, remove the cap and
discard the solution collected in the tube.
9. Replace the cap and the resin column and continue adding sample water
to the column, using the pipet, until exactly 10 mL has been collected in
the test tube. Remove the cap and column.
10. Add 3 drops of *Methyl Orange Indicator, 0.1% w/Halidex (2299). Cap
and mix. Solution will turn red.
11. Fill the second Titrator with *TDS Reagent B (4803DR). Titrate the
sample until the red color changes to yellow. Read the test result directly
from the scale where the large ring on the Titrator meets the Titrator
barrel. Record as Result B.
12. Add Result A and Result B. Record as ppm total dissolved solids as
CaCO
3
.
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