Dialysis-solid-phase extraction combined on-line with non-aqueous capillary electrophoresis for improved detectability of tricyclic antidepressants in biological samples

Dialysis-solid-phase extraction (SPE) sample pretreatment is combined on-li ne with non-aqueous capillary electrophoresis for the determination of tric yclic antidepressants in urine and serum. After clean-up and enrichment, th e water is removed from the sample matrix and the analytes are eluted from the cartridge by means of an organic solvent. Next, the eluate is transport ed to the capillary and the injection is performed electrokinetically. This injection, which does not suffer from an adverse sample matrix effect beca use of the SPE step, results in further analyte concentration. The detectio n limits are in the 0.02-0.1 mug/ml range and the day-to-day repeatabilitie s are between 2.5 and 9.5%, which is quite satisfactory. (C) 2001 Elsevier Science B.V. All rights reserved.