Packaging and storage—
Preserve in well-closed containers.
Identification—
A:
Dissolve about 200 mg in 5 mL of 3 N hydrochloric acid, and add, with stirring, 1 mL of sodium nitrite solution (1 in 2). Chill in an ice bath for 15 minutes, stirring if necessary, to induce crystallization, filter the precipitate on a sintered-glass funnel, wash with 10 mL of cold water, and dry at 105
: the
N,
N¢-dinitrosopiperazine so obtained melts between 156
and 160
.
Primary amines and ammonia—
Dissolve 500 mg in 10 mL of water. Add 1 mL of 2.5 N sodium hydroxide, 1 mL of acetone, and 1 mL of
sodium nitroferricyanide TS. Mix, and allow to stand for 10 minutes, accurately timed. Determine the absorbance of this solution at 520 nm and at 600 nm, using a blank consisting of the same quantities of the same reagents, but substituting water for the sodium hydroxide solution. The ratio
A600/
A520 is not more than 0.50 (equivalent to about 0.7% of primary amines and ammonia).
Assay—
Dissolve about 200 mg of Piperazine Citrate, accurately weighed, in 100 mL of
glacial acetic acid TS, warming slightly if necessary to effect solution. Add
crystal violet TS, and titrate with 0.1 N perchloric acid VS. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 10.71 mg of (C
4H
10N
2)
3·2C
6H
8O
7.
;)
191
.