Solid-phase extraction for the determination of tricyclic antidepressants in serum using a novel polymeric extraction sorbent

A fast and easy solid-phase extraction method was developed for the determination of amitriptyline, doxepin and their metabolites (nortriptyline and nordoxepin) in porcine serum matrix by high performance liquid chromatography. The spiked serum sample was pretreated with 2% phosphoric acid followed by a simple and rugged SPE procedure using Oasis(TM) HLB extraction cartridges. The SPE method requires only one mt of simple solvent throughout the entire SPE process. High and reproducible recoveries were obtained even though the cartridges ran dry. For five replicate analyses, the average recoveries of parent tricyclic antidepressants and their metabolites were all greater than 94%, and the RSDs were all less than 4.0%.