Quality control methods for

Methyl myristate R. C
15
H
30
O
2
. 
Description. A colourless or slightly yellow liquid.
Mass density (ρ
20
). About 0.87kg/l. 
A suitable commercially available reagent. 

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Quality control methods for medicinal plant materials 
Methyl orange R. Sodium salt of 4'-dimethylaminoazobenzene-4-sulfonic acid, 
C
14
H
14
N
3
NaO
3
S. 
A suitable commercially available reagent. 
Methyl orange/ethanol TS. 
Procedure. Dissolve 0.04g of methyl orange R in sufficient ethanol (∼1508/l) TS to 
produce 100ml. 
Methyl palmitate R. Methyl hexadecanoate; C
17
H
34
O
2
.
Description. A colourless, waxy solid. 
Freezing point. About 27°C. 
Mass density (ρ
20
). About 0.86kg/l. 
A suitable commercially available reagent. 
Methyl stearate R. C
19
H
38
O
2
. 
Description. A white or pale yellow, crystalline mass.
Melting point. About 38°C. 
A suitable commercially available reagent. 
1-Naphthol R. C
10
H
8
O. 
Description. Colourless crystals or a white, crystalline powder; odour, 
characteristic.
Solubility. Soluble in 5 parts of ethanol (∼750 g/l) TS (may form a slightly 
opalescent, colourless or almost colourless solution). 
Melting range. 93-96°C. 
Sulfated ash. Not more than 0.5 mg/g. 
A suitable commercially available reagent. 
1-Naphthol TS. 
Procedure. Dissolve 20g of 1-naphthol R in 100ml of ethanol (∼750g/l) TS. Protect 
from light and use within a few days of preparation.