Sodium hydroxide
insoluble matter
(Vol. 4)
Not more than 2% on the dried basis
Weigh accurately about 1 g of the sample and dissolve in 100 ml of
sodium hydroxide TS, centrifuge and decant. Wash the residue five times
with water by mixing, centrifuging and decanting. Transfer the residue by
means of water to a tared fine glass filter, dry for 1 h at 105 o , cool and
weigh. Calculate as percentage of the dry weight.