Sample preparation with fiber-in-tube solid-phase microextraction for capillary electrophoretic separation of tricyclic antidepressant drugs in humanurine

Solid-phase microextraction (SPME) is a solvent-free sample preparation tec hnique using a thin coating attached to the surface of a fused silica-fiber as the extraction medium, which has been successfully applied to the analy sis of a wide variety of compounds by coupling to gas chromatography (GC). In recent years, in-tube SPME using GC capillary column as the extraction m edium has also been developed and coupled with liquid chromatography (LC) f or the preconcentration of nonvolatile compounds. In this study, an on-line interface between the fiber-in-tube SPME and capillary electrophoresis (CE ) has been developed, and the preconcentration and separation of four tricy clic antidepressant (TCA) drugs, amitriptyline, imipramine, nortriptyline, and desipramine, were performed with the hyphenated system. Under the optim ized condition, a better extraction performance than conventional in-tube S PME was obtained, even the length of the extraction medium was much shorter . The results clearly indicated that the fiber was working effectively as a n extraction medium. For the separation of these four TCAs, capillary elect rophoretic separation with beta -cyclodextrin as the buffer additive has be en employed and the application of the developed system to the analysis of complex sample mixtures in a biological matrix is also demonstrated.