Spectrophotometric determination of piperazine with chloranil.

Piperazine and its salts were determined by spectrophotometry by complex formation with chloranil in an aq. ethanol medium, without prior separation of the free base, and measurement of the absorbance of the complex at 382 nm. Beer's law was obeyed for 1 to 6 µg ml-1 of piperazine and 2 to 12 µg ml-1 of its salts. The ɛ values were 12,400 for piperazine, piperazinium dichloride and piperazinium phosphate and 35,300 for piperazinium citrate; the mean recoveries were 97.8 ± 0.19, 99.6 ± 0.19, 101.4 ± 0.08 and 99.8 ± 0.12% for piperazine and its chloride, citrate and phosphate salts, respectively. The method was successfully applied to the determination of piperazine in four commercial pharmaceutical preparations; primary and secondary arylamines, amino-acids, phenols, naphthalene and degradation products of piperazine (if containing imino- or amino-groups) interfered