Screening and semi-quantitative analysis of post mortem blood for basic drugs using gas chromatography/ion trap mass spectrometry

The study presented here shows that GC–MS with ion trap detection can be used for screening post mortem blood. The method described was used to simultaneously screen for unknowns, identify basic drugs present and semi-quantitate 14 drugs commonly encountered in coronerʹs toxicology (i.e. was used to determine whether the drugs were present in sub-therapeutic, therapeutic or greater than therapeutic amounts). The equipment used included a Varian Saturn 2000 GC–MS operating in full scan mode, a CP-3800 GC, a CP-8400 autosampler and Saturn GC–MS workstation Version 5.5 software. Post mortem blood samples were extracted using a standard liquid–liquid procedure; diethylether followed by back extraction into 0.1 M HCl. Standard curves for the 14 drugs which were semi-quantitated (amitriptyline, citalopram, clozapine, cocaine, cyclizine, diazepam, dihydrocodeine, dothiepin, methadone, mirtazapine, procyclidine, sertraline, tramadol, venlafaxine) were prepared covering the concentration range 0–1.0 ug/mL. The procedure is in routine use for coroners toxicology; semi-quantitation has been used (i) to speed-up the through put of cases where drugs are an incidental finding and (ii) for cases where the amount of sample submitted for analysis was too small to allow for screening, identification and quantitation on separate sample volumes.