A:
Finely powder a number of Tablets, equivalent to about 200 mg of piperazine citrate, mix with 5 mL of 3 N hydrochloric acid, and filter. To the filtrate 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
.
B:
To a quantity of powdered Tablets, equivalent to about 500 mg of piperazine citrate, add 10 mL of water, shake, and filter: the filtrate responds to the tests for
Citrate 
191
.
