Quality control methods for

Potassium dihydrogen phosphate R. KH
2
PO
4
.
A suitable commercially available reagent. 
Potassium hydrogen phthalate R. C
8
H
5
KO
4
.
A suitable commercially available reagent. 
Potassium hydroxide R. KOH. 
A suitable commercially available reagent. 
Potassium hydroxide (∼110 g/l) TS. A solution of potassium hydroxide R 
containing about 112 g of KOH per litre (approximately 2 mol/l). 
Potassium hydroxide (∼55 g/l) TS. A solution of potassium hydroxide R 
containing about 56g of KOH per litre (approximately 1 mol/l). 
Potassium iodide R. KI. 
A suitable commercially available reagent. 
Potassium iodide AsR. Potassium iodide R that complies with the following 
test: Dissolve 10g of potassium iodide R in 25 ml of hydrochloric acid (∼250g/l) 
AsTS and 35 ml of water, add 2 drops of stannous chloride AsTS and apply the 
general test for arsenic; no visible stain is produced. 
 
Potassium iodide (80 g/l) TS. A solution of potassium iodide R containing about 
83 g of KI per litre (approximately 0.5 mol/l). 
Potassium sulfate R. K
2
SO
4
. 
A suitable commercially available reagent. 
Potassium tellurite R. K
2
TeO
3
(approx.)
A suitable commercially available reagent. 
Potassium tetrathionate R. K
2
S
4
O
6
. 
A suitable commercially available reagent. 
Prometryn R. C
10
H
19
N
5
S. 
A commercially available reagent suitable for use as a reference material. 
1-Propanol R. n-Propanol; propan-1-ol, C
3
H
8
O.
Description. A clear, colourless liquid. 
Miscibility. Miscible with water and ethanol (∼750g/l) TS.

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Quality control methods for medicinal plant materials 
Boiling range. Not less than 95% distils between 95 and 98°C.
Mass density (ρ
20
). About 0.803 kg/l. 
Residue on evaporation. Evaporate on a water-bath and dry to constant weight at 
105°C; leaves a residue of not more than 0.1 mg/g. 
A suitable commercially available reagent.