LaMotte AST Series Professional Soil Test Outfits - Manual (Page 28)

PROCEDURE
Read the Direct Reading Titrator instructions on page 6 before
proceeding.
DILUTION OF SOIL EXTRACT
1.
Use the graduated cylinder (0417) to transfer 10 mL of soil extract
to a 50 mL beaker (0944).
2. Add 10 mL of deionized water. Mix and neutralize.
NOTE: See Neutralization of Soil Extract, page 15.
TITRATION A: CALCIUM & MAGNESIUM
1.
Fill test tube (0778) to 5 mL line with diluted soil extract. Dilute to
10 mL line with deionized water.
2. Add 5 drops of Calcium-Magnesium Inhibitor Reagent (3922).
Swirl to mix. Wait 5 minutes.
3. Add 5 drops of *Calcium & Magnesium Buffer (5126). Swirl to mix.
4. Add 10 drops of *CM Indicator Reagent (6522). Swirl to mix.
Solution will turn red.
5. Fill the Direct Reading Titrator (0384) with Standard EDTA
Reagent (5254). Insert Titrator tip into the center hole of the test
tube cap.
6. While swirling the tube, slowly press the plunger to titrate sample
until color changes from red to blue.
7. Read the result where the plunger tip meets the scale. Multiply by
5.16. Record as Value A.
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