# Fertilisers (Sampling and Analysis) Regulations (Northern Ireland) 1996, Paragraph 3: REAGENTS


3.1 Activated charcoal.
Carrez solution I:
3.2 dissolve 21.9 g zinc acetate dihydrate in water, add 3 ml glacial acetic acid and dilute to 100 ml with water.
Carrez solution II:
3.3 10.6 g potassium ferrocyanide per 100 ml.
3.4 Hydrochloric acid solution, 0.02 M.
3.5 Sodium acetate solution, 136 g sodium acetate trihydrate per litre.
4-dimethylaminobenzaldehyde solution:
3.6 dissolve 1.6 g of 4-dimethylaminobenzaldehyde (4-DMAB) in 100 ml 96% ethanol and add 10 ml of hydrochloric acid (ρ = 1.18 g/ml).
3.7 Urea standard solution: 1.0 g per 100 ml (1 ml of this solution = 10 mg urea).

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Source: https://www.legislation.gov.uk/nisr/1996/513/schedule/2/part/II/chapter/4./paragraph/3 (the official version)
Page: https://openlegislation.uk/fertilisers-sampling-and-analysis-regulations-northern-ireland-1996/schedule-2/part-II/chapter-4./paragraph-3
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.