# Fertilisers (Sampling and Analysis) Regulations (Northern Ireland) 1996, Paragraph 4: REAGENTS


4.1 Hydrochloric acid, 1 M solution.
4.2 Hydrochloric acid, 0.5 M solution.
4.3 Standard solution of magnesium, 1.00 mg per ml.
4.3.1 Dissolve 1.013 g of magnesium sulfate (MgSO4.7H2O) in 0.5 M in hydrochloric acid solution (4.2).
or:
4.3.2 Weigh out 1.658 g of magnesium oxide (MgO), previously ashed to removed all traces of carbonate. Place in a beaker with 100 ml of water and 120 ml of 1 M hydrochloric acid (4.1). When it has dissolved, transfer quantitatively into a 1 litre graduated flask. Make up to the volume and mix.
or:
4.3.3 Commercial standard solution.
The laboratory is responsible for testing such solutions.
4.4 Strontium chloride solution.
Dissolve 75 g of strontium chloride (SrCl26H2O) in the hydrochloric acid solution (4.2) and make up to 500 ml with the same acid solution.

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Source: https://www.legislation.gov.uk/nisr/1996/513/schedule/2/part/I/chapter/21./paragraph/4 (the official version)
Page: https://openlegislation.uk/fertilisers-sampling-and-analysis-regulations-northern-ireland-1996/schedule-2/part-I/chapter-21./paragraph-4
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.