LaMotte AST Series Professional Soil Test Outfits - Manual (Page 29)

TITRATION B: CALCIUM
1.
Fill test tube (0778) to 5 mL line with diluted soil extract. Dilute to
10 mL line with deionized water.
2. Add 2 drops of *Inhibitor Solution (9258). Swirl to mix.
3. Add 2 drops of *TEA Reagent (3921). Swirl to mix.
4. Add 8 drops of *Sodium Hydroxide Reagent w/Metal Inhibitors
(4259). Swirl to mix.
5. Add one Calcium Hardness Indicator Tablet (T-5250). Cap and
swirl until tablet disintegrates. Solution will turn red.
6. Fill the Direct Reading Titrator (0384) with Standard EDTA
Reagent (5254). Insert Titrator tip into the center hole of the test
tube cap.
7. While swirling the tube, slowly press the plunger to titrate sample
until color changes from red to blue, and does not revert to red for at
least one minute.
8. Read the result where the plunger tip meets the scale. Multiply by
5.16. Record as Value B.
FINAL RESULTS
Calcium:
Value B x 0.4 = ppm Ca
Magnesium:
0.24 (Value A
- Value B) = ppm Mg
NOTE: To obtain results in lb/acre, multiply results by 2.
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