# Fertilisers (Sampling and Analysis) Regulations (Northern Ireland) 1996, Paragraph 7: PROCEDURE


7.1 Test sample
Take a quantity of fertiliser weighing 1 or 2 g depending on the declared content of the product. The following table shall be used to obtain a final solution which, after appropriate dilution, will be within the measuring range for each method. The samples should be weighed to within 1 mg.
Declared content of trace element in the fertiliser (%)
> 10-< 25
≥ 25
Mass of test sample (g)
2
1
Mass of element in the sample (mg)
> 200-< 500
≥ 250
Volume of extract V (ml)
500
500
Concentration of element in extract (mg/l)
> 400-<1000
≥ 500
Place the sample in a 500 ml flask.
Preparation of the solution
7.2 Add about 400 ml of water.
Stopper the flask well. Shake vigorously by hand to disperse the sample, then place the flask on the shaker and shake for 30 minutes.
Make up to volume with water and mix thoroughly.
Preparation of the test solution
7.3 Filter immediately into a clean, dry flask. Stopper the flask. Carry out the determination immediately after filtering.
Note:
If the filtrate gradually becomes cloudy, make another extraction following 7.1 and 7.2 in a flask of volume Ve. Filter into a calibrated flask of volume W which has previously been dried and has received 5 ml of dilute hydrochloric acid (4.1). Stop the filtration at the exact moment when the calibration mark is reached. Mix thoroughly.
Under these conditions the value of V in the expression of results is:
V=Ve×W/(W-5)
The dilutions in the expression of results depend on this value of V.

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Source: https://www.legislation.gov.uk/nisr/1996/513/schedule/2/part/I/chapter/26b./paragraph/7 (the official version)
Page: https://openlegislation.uk/fertilisers-sampling-and-analysis-regulations-northern-ireland-1996/schedule-2/part-I/chapter-26b./paragraph-7
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.