A new method for the determination of residual piperazine in pharmaceuticals by capillary gas chromatography

A new selective open tubular capillary gas chromatographic method is developed for the determination of trace amounts of piperazine. Piperazine is extracted from pharmaceuticals into cyclohexane and is partitioned with water. The aqueous solution is then injected into a 5% crosslinked Ph-Me silicone column programmed at 50–180 °C for 10 min. Piperazine is eluted after 3.18 min under isothermal conditions. The lower limit of determination is 0.4 ppm. This method has been successfully applied for the assay of piperazine in pharmaceutical formulations and its trace determination in fluoroquinolone drugs such as norfloxacin and ciprofloxacin. The method is reproducible and the standard and relative standard deviation for 10 repeated injections of 2 μg piperazine are 0.7 and ±2.1% respectively.