Paragraph 8 EXPRESSION OF RESULTS

See Method 26d (8).

The percentage of zinc in the fertiliser is given by:

$$\mathrm{Zn}\left(\mathrm{\%}\right)=\mathrm{[}\left(\mathrm{x}\mathrm{s}-\mathrm{x}\mathrm{b}\right)\times \mathrm{V}\times \mathrm{D]}/\left(\mathrm{M}\times 104\right)$$

If Method 26c has been used:

$$\mathrm{Zn}\left(\mathrm{\%}\right)=\mathrm{[}\left(\mathrm{x}\mathrm{s}-\mathrm{x}\mathrm{b}\right)\times \mathrm{V}\times \mathrm{2D]}/\left(\mathrm{M}\times 104\right)$$

where:

• Zn is the quantity of zinc expressed as a percentage of the fertiliser;

• x_s is the concentration in μg/ml of the test solution;

• x_b is the concentration in μg/ml of the blank solution;

• V is the volume in ml of the extract solution obtained in accordance with Methods 26a or 26b;

• D is the factor corresponding to the dilution performed in (6.2);

• M is the mass in g of the test sample taken in accordance with Methods 26a or 26b.

Calculation of the dilution factor D: if (a₁), (a₂), (a₃), . . . , (a_i) and (a) are successive aliquot portions and (v₁), (v₂), (v₃), . . . , (v_i) and (100) are the volumes in ml corresponding to their respective dilutions, the dilution factor D will be:

$$\mathrm{D}=(\mathrm{v}1/\mathrm{a}1)\times (\mathrm{v}2/\mathrm{a}2)\times (\mathrm{v}3/\mathrm{a}3)\text{x . . . x (v}\mathrm{i}/\mathrm{a}\mathrm{i})\times (100/\mathrm{a})\mathrm{.}$$