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


4.1 Nitrobenzene or diethyl ether.
4.2 Nitric acid, 10 M solution.
4.3 Indicator solution: dissolve 40 g of ferric ammonium sulfate [Fe2(SO4)3.(NH4)2SO4.24H2O] in water and make up to 1 litre.
4.4 Silver nitrate, 0.1 M solution.
4.5 Ammonium thiocyanate, 0.1 M solution.
Preparation: since this salt is hygroscopic and cannot be dried without risk of decomposition, it is advisable to weigh out approximately 9 g, dissolve in water and make up the volume to one litre. Standardise by titration against 0.1 M silver nitrate solution.
4.6 Potassium chloride solution: Dissolve 2.103 g of potassium chloride, previously dried at 130°C, for one hour, in water and make up to 500 ml.

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Source: https://www.legislation.gov.uk/nisr/1996/513/schedule/2/part/I/chapter/12./paragraph/4 (the official version)
Page: https://openlegislation.uk/fertilisers-sampling-and-analysis-regulations-northern-ireland-1996/schedule-2/part-I/chapter-12./paragraph-4
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.