A fast screening method for tricyclic antidepressants and their urinary metabolites by FAB‐tandem mass spectrometry

Abstract

A screening method for tricyclic antidepressants (TCA) and their urinary metabolites by FAB tandem mass spectrometry (FAB MS/MS) is presented. The collision induced dissociation (CID) behavior of pure dibenzocycloheptadienes (amitriptyline1, nortriptyline2), dibenzoxepines (doxepine3, dosulepine4), dibenzazepines (imipramine5, desipramine6, trimipramine7) and the iminostilbene derivative opipramol8is described and used for the specific determination of these tricyclics by MS/MS.For the screening procedure a methanolic extract of the urine sample is passed through a XAD-2 column and the eluate is examined without further purification after evaporation of the solvent. Identification of the TCA is achieved by constant neutral loss (CNL) scans for 173 u, 195 u and 193 u and subsequent daughter ion spectra of the molecular ions [M+H]+. Glucuronide conjugate metabolites of the tricyclic antidepressants1,2,3,6,8could be identified by CNL-scans (176 u) and the assignments were confirmed by daughter ion mass spectra. A urine sample of a fatal1,2,8overdose and samples of three patients under therapeutic dosage with1,3or6are presented as examples for application.