Determination of tricyclic antidepressants in human plasma by micellar electrokinetic capillary chromatography.

The factors affecting the micellar electrokinetic chromatographic separation of structurally similar tricyclic antidepressants (imipramine, amitriptyline, desipramine, nortriptyline, doxepin and trimipramine as an internal standard) were investigated by changing the species of micelles, and adding an organic modifier (urea or methanol) to the micellar solution. The determination of tricyclic antidepressants in human plasma is demonstrated under the optimum separation conditions using 37.5 mM phosphate buffer (pH 8.0) containing 25 mM dodecyltrimethylammonium bromide and 2 M urea at -25 kV applied voltage.