Capillary electrophoresis–mass spectrometry, liquid chromatography–mass spectrometry and nanoelectrospray-mass spectrometry of praziquantel metabolites

Capillary electrophoresis–mass spectrometry (CE–MS) and liquid chromatography–mass spectrometry (LC–MS) coupling was used for the investigation of metabolites of the anthelmintic drug praziquantel. Human urine samples and microsomal incubation mixtures were investigated after preparation by solid-phase extraction. CE– and LC–MS coupling was performed using an electrospray ionization interface. An ion trap mass spectrometer equipped with a laboratory-made nanoelectrospray ion source was used for the investigation of the glucuronide conjugates by consecutive fragmentations. The nanoelectrospray interface offers the opportunity to perform complicated MSn spectrometric investigations. Different phase I metabolites of praziquantel and their glucuronidated and sulfated conjugates were detected.