Highly selective and sensitive determination of tricyclic antidepressants in human plasma using high-performance liquid chromatography with post-column tris(2,2′-bipyridyl) ruthenium(III) chemiluminescence detection Original Research Article

A simple, selective and sensitive determination method of tricyclic antidepressants (imipramine, desipramine, amitriptyline, nortriptyline and clomipramine) has been developed using high-performance liquid chromatography (HPLC) with chemiluminescence detection. The method is based on the detection of aliphatic secondary or tertiary amino moieties in antidepressants with post-column tris(2,2′-bipyridyl)ruthenium(III) chemiluminescence. Five antidepressants were separated on a trimethylsilyl (TMS) column using a mixture of 50 mM phosphate buffer (pH 7.0) and acetonitrile (55:45, v/v) as a mobile phase. The eluate was on-line mixed with acidic tris(2,2′-bipyridyl)ruthenium(III) solution and the generated chemiluminescence was detected. The detection limits (signal-to-noise ratio=3) for antidepressants examined were 3.2–33.1 pg (12–105 fmol), for an injection volume of 20 μl. This HPLC system could sensitively detect other tri- or tetracyclic antidepressants and was successfully applied to the determination of imipramine and amitriptyline in human plasma after purification by two-step liquid–liquid extraction.