[Determination of piperazine in hen eggs with HPLC following oral administration]

After oral administration of piperazine citrate to hens, this antihelmintic agent appeared unchanged in the eggs. After a therapeutic dose of ca. 0.9 g piperazine citrate per hen, a maximum level of 1.5 mg piperazine/kg egg was found two days after the application. The elimination half-life was 29 h and piperazine was found in the eggs up to 17 days after administration (limit of detection: 1 microgram/kg). Piperazine determination was performed by HPLC of the dansylderivative after clean-up by TLC.