ONLINE CAPILLARY ELECTROPHORESIS-ELECTROSPRAY IONIZATION MASS-SPECTROMETRY USING A POLYMERIZED ANIONIC SURFACTANT

On-line capillary electrophoresis - electrospray ionization - mass spe ctrometry (CE-ESI-MS) has been used to determine the tricyclic antidep ressant drugs (imipramine, doxepin, and amitriptyline) as well as the beta-adrenergic blocker drugs (propranolol and alprenolol). A CE-ESI-M S interface linking a manually operated CE system and a Finnigan MAT-9 00 sector mass spectrometer (with an Analytica electrospray ionization source) has been constructed in-house and employed for this study. Al though a water/methanol based capillary zone electrophoresis (CZE) buf fer was initially used to determine these analytes, enhanced resolutio n was obtained by addition of a polymerized surfactant, i.e., poly-sod ium undecylenic sulfate (poly-SUS), into the electrokinetic chromatogr aphy (EKC) buffer. When a low concentration of this poly-SUS surfactan t was added to a volatile EKC buffer, these structurally similar catio nic drugs were EKC separated and on-line detected by ESI-MS.