The development of a LC-MS/MS general unknown screening procedure for toxicologically relevant substances in blood samples by means of information-dependent acquisition on a Q-TOF is reported. IDA is an artificial intelligence-based product ion scan mode providing automatic "on-the-fly" MS to MS/MS switching. By performing information-dependent scanning at two different fragmentation energies, two collision-induced dissociation product ion spectra for each of the detected compounds are generated. As such, information-rich MS/MS spectra are obtained from precursor ions not known beforehand. In addition, limitation of the MS/MS acquisition time to an acceptable minimum resulted in an almost instantaneous switch back to the MS mode. As such, this approach provided MS chromatograms that still could be of use for semiquantitative purposes. Since the switching intensity threshold, unequivocally related to the background noise, proved a critical parameter, the solid-phase extraction procedure, the liquid chromatographic conditions, and the mass spectrometric parameters all were optimized to the advantage of information-dependent acquisition. Finally, the screening procedure we developed was benchmarked, on one hand, qualitatively against the results obtained from traditional GUS approaches in a number of routine toxicological laboratories (20 samples) and, on the other hand, quantitatively with respect to its potential against established LC-MS/MS methods (7 samples). The procedure performed very well from a qualitative point of view; almost all of the drugs detected by the conventional techniques were identified, as well as additional drugs that were not previously reported. The procedure proved well-suited for an initial semiquantitative assessment, as is customary in, for example, forensic toxicology before accurate intoxication levels are determined using targeted analytical analyses.
In this study, regional tissue distributions of the amphetamine analogue 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") and its metabolite 3,4-methylenedioxyamphetamine (MDA) in a fatal overdose are presented. Quantitation of MDMA and MDA levels occurred in blood samples taken centrally (right and left heart and main adjacent great vessels) and peripherally (subclavian and femoral blood). In addition, MDMA and MDA concentrations were determined in cardiac and iliopsoas muscle, both lungs, liver, both kidneys, spleen, the four brain lobes, cerebellum and brainstem, and adipose tissue. Finally, MDMA and MDA levels were determined in serum, vitreous humor, urine, and bile. For all samples, a fully validated high-pressure liquid chromatography procedure with fluorescence detection was used. The found substances were also identified with liquid chromatography-tandem mass spectrometry. Our data confirm that blood sampling from an isolated peripheral vein is recommended for MDMA and MDA. In addition, the vitreous humor MDMA level indicates that this fluid can be an interesting alternative when a suitable blood sample is missing. Considering the substantial differences in concentrations in blood samples taken from various sites in the body and the high levels in some tissues (e.g., in liver), we concluded that the influence of postmortem redistribution should be taken into account in the interpretation of toxicological data when an appropriate peripheral sample cannot be obtained or when blood samples are not available because of putrefaction.
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