Quality control methods for

Chloral hydrate R. C
2
H
3
Cl
3
O
2
. 
Description. Colourless, hygroscopic crystals with a sharp odour. Melting 
temperature. About 55°C. 
A suitable commercially available reagent. 
Chloral hydrate TS. 
Procedure. Dissolve 50g of chloral hydrate R in 20 ml of water. 
Chloramphenicol R. C
11
H
12
Cl
2
N
2
O
5
. Quality conforms to the monograph in The 
international pharmacopoeia, Vol. 2, p. 64. 
Chloroform R. CHCl
3
. 
A suitable commercially available reagent. 

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Quality control methods for medicinal plant materials 
Chromic acid TS. 
Procedure. Dissolve 84g of chromium trioxide R in 700 ml of water and add 
slowly, with stirring, 400ml of sulfuric acid (∼1760g/l) TS. 
Chromium trioxide R. CrO
3
. 
A suitable commercially available reagent. 
Copper(11) sulfate R. CuSO
4
,5H
2
O. 
A suitable commercially available reagent. 
Crystal violet R. C
25
H
30
ClN
3
. 
A suitable commercially available reagent. 
Cuoxam TS. Tetramine copper dihydroxide, Schweizer's reagent. 
Procedure. Dissolve 10g of copper(II) sulfate R in 100 ml of water, and add 
sufficient sodium hydroxide (∼240g/l) TS until alkaline. Filter the precipitate 
and wash with cold water, previously made sulfate-free. To the moist copper 
hydroxide add, while stirring, ammonia (∼100g/l) TS until dissolved. 
Note. Cuoxam TS must be freshly prepared. 
Cyclohexane R. C
6
H
12
. 
A suitable commercially available reagent. 
 
Desmetryn R. C
9
H
17
N
5
S; 2-methylmercapto-4-methylamino-6-isopropylamino-
S-triazine. 
A commercially available reagent suitable for use as a reference material.