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ASSAY
Determine the density (2.2.5) of the solution to be examined.
Dilute 4.00 g to 100.0 ml with water R. Transfer 25.0 ml
of the solution to a separating funnel, add 25 ml of
chloroform R, 10 ml of 0.1 M sodium hydroxide and 10.0 ml
of a freshly prepared 50 g/l solution of potassium iodide R.
Shake well, allow to separate and discard the chloroform
layer. Shake the aqueous layer with three quantities, each
of 10 ml, of chloroform R and discard the chloroform layers.
To the aqueous layer add 40 ml of hydrochloric acid R,
allow to cool and titrate with 0.05 M potassium iodate until
the deep-brown colour is almost discharged. Add 2 ml of
chloroform R and continue the titration, shaking vigorously,
until the chloroform layer no longer changes colour. Carry
out a blank titration on a mixture of 10.0 ml of the freshly
prepared 50 g/l solution of potassium iodide R, 20 ml of
water R and 40 ml of hydrochloric acid R.
1 ml of 0.05 Mpotassium iodate is equivalent to 35.4 mg
of C22H40ClN. |
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