Paragraph 7 PREPARATION OF SOLUTIONS TO BE MEASURED
Depending upon the expected sodium content of the extraction solution as in method 15 or 17 (5 g of fertiliser in 500 ml), carry out the dilutions in accordance with the following table:
| Intermediate dilution | Final dilution | |||||
|---|---|---|---|---|---|---|
| Na2O (%) | Na (%) | Sample (ml) (v2) | Dilution to ml (v3) | Sample (ml) (v4) | Dilution to ml | Degree of dilution |
| 3-5 | 2.2-3.7 | 10 | 50 | 10 | 100 | 50 |
| 5-10 | 3.7-7.4 | 10 | 100 | 10 | 100 | 100 |
| 10-20 | 7.4-15 | 10 | 100 | 5 | 100 | 200 |
| 20-38 | 15-28 | 5 | 100 | 5 | 100 | 400 |
Make up the intermediate dilution with water. For the final dilution add 10 ml of the solution (4.5) to the 100 ml graduated flask.
For a test sample of 1 g multiply the volume of the final dilution (v4) by five.