Capillary electrophoresis screening method for six tricyclic antidepressants in human serum.

A capillary electrophoretic (CE) method for screening of six tricyclic antidepressants: amitriptyline, nortriptyline, imipramine, desipramine, doxepin and nordoxepin, in human serum, has been developed. The drugs were separated in a bare fused silica capillary (50 microm i.d.) using the background electrolyte: 50 mM CAPSO (pH 9.54) in methanol/water with KCI addition. For increasing the method sensitivity, the sample concentration in the capillary (sample stacking) using pressure and electrokinetic injection has been applied. The standard addition method was used for calibration of the developed analytical procedure. The precision of the identification parameter (the relative migration time) and the quantitative parameter (the relative peak area) was within the range of 0.05-1.65 and 0.73-6.7 (RSD %), respectively. The detection limits were found to be 30 ng/mL for desipramine, 62.5 ng/mL for nortriptyline, and 50 ng/mL for remaining analytes.