Fertilisers (Sampling and Analysis) Regulations (Northern Ireland) 1996

EXPRESSION OF RESULTS

8.  See Method 25d (8).

The percentage of zinc in the fertiliser is:

If Method 25c has been used:

where:

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

• x_s is the mass in μg of Zn in the test solution (6.2);

• x_b is the mass in μg of Zn in the blank solution (7.1);

• V is the volume in ml of the extract solution obtained in accordance with Method 25a or 25b;

• 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 Method 25a or 25b.

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

D = (v1 / a1) × (v2 / a2) × (v3 / a3)x . . . x (vi / ai) × (100 / a).