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


4.1 Methanol.
4.2 Sulfuric acid solution, approximately 0.05 M.
4.3 Sodium hydroxide solution, approximately 0.1 M.
4.4 Alkaline solution of potassium sodium tartrate:
In a 1 litre graduated flask dissolve 40 g of sodium hydroxide in 500 ml of water and leave to cool. Add 50 g of potassium sodium tartrate (KNaC4H4O6.4H2O). Make up to the mark and mix. Leave standing 24 hours before use.
4.5 Copper sulfate solution:
In a 1 litre graduated flask dissolve 15 g of copper sulfate (CuSO4.5H2O) in 500 ml of water. Make up to the mark and mix.
4.6 Biuret standard solution:
In a 250 ml graduated flask, dissolve 0.250 g of pure biuret in water. Make up to the mark and mix. 1 ml of this solution contains 0.001 g of biuret. This solution should be freshly prepared.
4.7 Methyl red indicator solution:
Dissolve 0.1 g methyl red in 50 ml 95% ethanol and make up to 100 ml with water. Filter if necessary.

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Source: https://www.legislation.gov.uk/nisr/1996/513/schedule/2/part/I/chapter/7./paragraph/4 (the official version)
Page: https://openlegislation.uk/fertilisers-sampling-and-analysis-regulations-northern-ireland-1996/schedule-2/part-I/chapter-7./paragraph-4
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.