SCHEDULE 2METHODS OF ANALYSIS
10.DETERMINATION OF EXTRACTED PHOSPHORUS
7. EXPRESSION OF THE RESULTS
If the samples for analysis and dilutions shown in the Table are used the following formulae apply:
where:
A = weight in g of the quinoline phosphomolybdate
a = weight in g of the quinoline phosphomolybdate obtained in the blank test
F and F' = factors given in the last two columns of the Table.
With samples for analysis and dilutions which differ from those of the Table the following formulae apply:—
where:
f = conversion factor, quinoline phosphomolybdate into P20s = 0.03074
f' = conversion factor, quinoline phosphomolybdate into P = 0.013984
D = dilution factor
M = weighing of the sample analysed
| % P2O5 in the fertiliser | % P in the fertiliser | Sample for analysis g | Dilution to ml | Sample ml | Dilution to ml | Sample to be precipitated ml | Quinoline phosphomolybdate conversion factor (F) in percentage P2O5 | Quinoline phosphomolybdate conversion factor (F) in percentage P |
|---|---|---|---|---|---|---|---|---|
| 1-5 | 0.44 -2.2 | 1 2.5 5 | 500 500 500 | — — — | — — — | 100 50 25 | 16.037 12.830 12.830 | 6.992 5.594 5.594 |
| 5-10 | 2.2 -4.4 | 1 2.5 3 5 | 500 500 500 500 | — — — — | — — — — | 50 25 25 10 | 32.074 25.660 21.383 32.074 | 13.984 11.188 9.323 13.984 |
| 10-25 | 4.4 -11.0 | 1 2.5 3 5 | 500 500 500 500 | — — — 50 | — — — 500 | 25 10 10 50 | 64.148 64.148 53.457 64.148 | 27.968 27.968 23.307 27.968 |
| +25 | +11 | 1 2.5 3 5 | 500 500 500 500 | — 50 50 50 | — 500 500 500 | 10 50 50 25 | 160.370 128.296 106.913 128.296 | 69.921 55.937 46.614 55.937 |