Untargeted LC-HRMS impurity profiling for forensic chemical intelligence

Synthetic drugs pose a growing threat to public health and safety due to their rapid diversification, low production costs, and the ease of access to chemical precursors and reagents. Understanding the underlying synthetic processes is essential to support chemical intelligence and interventions targeting clandestine laboratories. While traditional targeted profiling relies on prior knowledge of substances and synthesis routes, untargeted approaches are crucial for emerging compounds whose synthetic pathways remain unknown. This study presents an untargeted analytical workflow integrating solid-phase microextraction headspace gas chromatography–mass spectrometry (SPME-HS-GC–MS) and liquid chromatography coupled to Orbitrap high-resolution mass spectrometry (LC-HRMS) for comprehensive impurity profiling of seized drug samples. Data were processed using Compound Discoverer, enabling automated feature annotation through integrated databases ( mzCloud , HighResNPS ) and FISh Scoring for structural elucidation. Applied to three seized nitazene samples, the workflow highlighted differences in impurity profiles that are consistent with variations in synthetic conditions and processes. In addition to the main active compounds, several intermediates, oxidation products, and trace-level new psychoactive substances (NPS), including cychlorphine, were putatively identified. The latter finding is notable given recent international alerts concerning orphine-type opioids associated with severe intoxications. Overall, the proposed strategy demonstrates the capability of untargeted LC-HRMS profiling to identify cross-production phenomena and previously unreported impurities, offering a data-driven tool for early detection of NPS and forensic chemical attribution of seizures.