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).