Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- Differentiation of selegiline metabolites and illicit methamphetamine and amphetamine use in elderly postmortem cases: Insights from LC-MS/MS and immunoassay techniquesPublication . Costa, Suzel; Rosendo, Luana M.; Barroso, Mário; Franco, João MiguelAbstract: Introduction: In forensic toxicology, distinguishing between pharmaceutical metabolites and illicit substances is crucial for accurate case interpretation. This study explores two post-mortem cases involving elderly individuals where methamphetamine and amphetamine were detected, raising initial concerns about illicit drug use. Aims: To demonstrate the application of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and immunoassay techniques in differentiating between selegiline metabolites and illicit methamphetamine and amphetamine. Methods: Blood samples from three deceased elderly individuals (ages 91 and 89) were analyzed using LC-MS/MS for the quantitative detection of selegiline and metabolites. Initial screening revealed methamphetamine and amphetamine levels suggestive of potential illicit use. Immunoassay testing for dextro isomers (those associated with drug abuse) was subsequently performed to differentiate between isomers. Results and Discussion: LC-MS/MS analysis confirmed selegiline in both cases, with methamphetamine and amphetamine detected. Immunoassay results were negative for dextro isomers, indicating that the detected substances were L-isomers, which is consistent with selegiline metabolism rather than illicit use. Conclusion: This study highlights the critical role of combining LC-MS/MS and immunoassay techniques in forensic toxicology. The negative immunoassay results for dextro isomers clarified that the methamphetamine and amphetamine present were metabolic byproducts of selegiline therapy. Accurate differentiation between therapeutic and illicit substances is essential to avoid misinterpretation, particularly in elderly individuals, where illicit drug use is infrequent. These findings emphasize the need for comprehensive analytical approaches in forensic investigations to ensure accurate and reliable results.
- High concentrations of nordiazepam may impair the detection of benzoylecgonine by GC-MS with derivatizationPublication . Costa, Suzel; Rosendo, Luana M.; Barroso, Mário; Gallardo, EugeniaIntroduction: Forensic toxicology plays a pivotal role in legal investigations, particularly in detecting substances in biological samples. However, the simultaneous presence of multiple substances can pose analytical challenges. For instance, nordiazepam, a major metabolite of some benzodiazepines, can interfere with the detection of benzoylecgonine, a primary metabolite of cocaine, when using gas chromatography-mass spectrometry (GC-MS) with N- methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA) derivatization. This interference could result in false negatives for benzoylecgonine detection. Aims: This study aims to assess whether N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide (MBDSTFA) derivatization can reduce interference from nordiazepam, thereby improving the detection and quantification of benzoylecgonine in biological samples. Methods: Solid phase extraction (SPE) was carried out on post-mortem blood samples using Oasis® MCX columns. Microwave derivatization with MSTFA or MBDSTFA followed after the extracts were evaporated. Results and discussion: Two derivatization reagents, MSTFA and MBDSTFA, were compared using GC-MS to evaluate their effectiveness. For this assessment, both the limit of detection (LOD) and limit of quantification (LOQ) for benzoylecgonine in this chromatographic method were 10 and 25 ng/mL, respectively. MBDSTFA derivatization significantly reduced analytical interference between nordiazepam and benzoylecgonine. In contrast, MSTFA derivatization resulted in substantial interference at high concentrations of nordiazepam, potentially leading to false negatives for cocaine detection. These findings highlight the superior performance of MBDSTFA in complex toxicological analyses. Conclusion: MBDSTFA derivatization is more effective than MSTFA for minimizing interference in the detection of benzoylecgonine in the presence of nordiazepam. This method enhances the specificity of forensic toxicological analyses and helps prevent false negatives for detecting cocaine consumption through its principal metabolite, thereby supporting more reliable legal and clinical decisions.